1. MCU,LDC BE General course information
Target group: Instructors, Technicians
Target of the course: To get the general knowledge and diagnosis method for newly applied hybrid components
Mandatory pre-courses:
To understand the system features and diagnosis for the MCU and LDC applied in TF Hybrid model.
Material:
Training vehicle (TF HEV)
Training Part (HPCU)
GDS
Instructors guide
Trainees textbook / File
Practice sheets
(Practice preparation)
Workshop manuals
Certificates
Nameplates
(Paper for notes)
(Pens etc.)
Method:
Lecture
Practice
Task
Lead over:
MCU,LDC
Learning
Objective
1. Understand the major features of HEV MCU.
2. Understand the structure and control system of HEV MCU.
3. Conduct periodic inspection and troubleshooting of EV MCU.
When viewing a hybrid vehicle’s engine room, the most significant difference between the hybrid vehicle and the gasoline or diesel vehicle is that the hybrid vehicle is equipped with a high voltage controller that includes a HPCU. The Hybrid Power Control Unit (HPCU) is composed of various components. It is the core device among the Power Electronics (referred to as ‘PE’) devices and acts as the brain. It commands the operation of the hybrid vehicle. It comprises a Hybrid Control Unit (HCU), an inverter (Motor Control Unit (MCU), a Generator Control Unit (GCU)) and a Low-voltage DC-DC Converter (LDC). All these components are configured as a single package. To ensure effective cooling of the HPCU, there is an additional cooling line which is separate to the existing engine cooling line. Each control unit is organically connected to the HCU via CAN communication.
In this chapter, the functions and roles of the MCU, which is a HPCU component that controls the motor, will be covered in detail and the interface between each unit will be described. Also covered in detail are a failsafe strategy for troubleshooting, procedure for cooling-line-related maintenance, error code conditions, and the meanings of the service data indicated on the diagnosis tool.
Copyright ⓒ 2010 All rights reserved. No part of this material may be reproduced, stored in any retrieval system or transmitted in any form or by any means without the written permission of Kia Motors Corporation.

2. Hydraulic Brake SystemBE
Configuration
The TF Hybrid Electric Vehicle with Transmission Mounted Electric Device (TMED), Parallel Type Hybrid System has integrated HCU, a main controller unit, LDC, an electric power converting device, and an MCU in a single HPCU. It is located at the LH position within the engine compartment. (The HPCU is a package concept that bundles important hybrid-related control devices.)
The major features of the HPCU are as follows:
1) Minimized device to device connecting wire ensuring higher quality as well as cost reduction by integrating the main control units into a single unit.
2) Quick response speed and higher reliability though application of Dual CAN (Chassis-CAN, Hybrid CAN).
3) More effective cooling of the heat generated by the operation of the unique hybrid components (such as MCU and LDC). This is achieved by replacing the air cooling system with a water cooling system. A more in-depth description of the HPCU cooling system is covered later in this chapter.
Hybrid Control Unit (HCU)
The HCU monitors driving conditions and the status of each of the various units. This allows control of the units to optimize driving conditions. It also takes on the main role of determining the power-train distribution of the electric motor, engine, etc., in the HEV. A more in-depth description of the control functions of the HCU is covered in the chapter of HCU.
Inverters (MCU, GCU)
The inverter supplies high voltage electric power to 2 major motors (traction motor, HSG) in the TF HEV. Depending on the driving conditions, the inverter communicates with the previously mentioned control devices (such as the HCU) and optimizes the 2 motors according to the driving conditions. Depending on the driving conditions, the traction motor and the HSG motor may take on the role of an alternator. In such case, the inverter takes on the role of a converter. The definition, concept and in-depth description of the inverter and the converter are detailed in another section.
Low Voltage DC-DC Converter (LDC)
The LDC is a DC converting device that converts high voltage power to low voltage (12V). It takes the place of the alternator in previous model vehicles, and supplies 12V power to various electrical loads in the vehicle and also recharges the back-up (auxiliary) battery. Together with the inverter, the LDC is an important device that determines the overall efficiency of the HEV.
To understand the overall layout and configuration of MCU & LDC.
Material:
Trainees textbook
Method:
Lecture
Lead over:
Configuration
Location of HPCU
A/T
High Vol. Battery
E-Oil Pump
Inverter 1
Hydraulic Brake System
Drive Motor
Inverter 2
HSG
LDC
HCU (Hybrid Control Unit)
Two Inverters
HPCU = HCU + Two Inverters + LDC ※ HPCU: Hybrid Power Control Unit
Water cooling heat sink
LDC

3. Specification HPCU LDC MCU HCU BE Specification Category Description
Hybrid Control Unit (HCU)
The HCU is integrated into the HPCU and is not a standalone component. It distributes power by controlling the engine and the motor. The most important deciding factor on fuel consumption in hybrid vehicle is determining when to activate the engine (at which RPM and torque). The HCU determines engine engagement and controls the engine output based on the driving conditions. In the event of failure of the major components, it controls the failsafe functions.
The main features of the HCU are:
- Supervisory control of HEV - Driver’s demand control - Power / Torque distribution (Mech. / Elec.) - Regenerative Brake Control - HEV system failsafe
Inverter (MCU, GCU)
A high-capacity power module is applied to control 2 primary motors using high voltage. The power module is composed of a high-speed switching insulated gate bipolar transistor (IGBT) and a diode circuit. The high voltage battery capacity is about 270V, but to ensure stability and reliability the power module uses high capacity power with a maximum voltage of 650V.
Low Voltage DC-DC Converter (LDC)
As previously mentioned, the LDC converts the high 270V power to 12V to be used by electrical loads in the vehicle. Because the LDC is not mechanically connected to the engine as in previous vehicles, the LDC provides stable output voltage even when the engine is not running. In addition, the LDC also recharges the auxiliary battery.
In general, the inverter, Motor Control Unit (MCU) and Generator Control Unit (GCU) are the same components which are named according to their function. The unit is called an inverter when describing its role of providing AC power to the 2 major motors. When describing its role of controlling the motor speed and torque in real-time with command from the HCU, it is called the MCU (when controlling the Traction Motor) or the GCU (when controlling the HSG Motor).
When charging the high voltage battery, the LDC takes on the role of AC-DC converter, and when controlling the motors using energy from the high voltage battery, the LDC takes on the role of DC-AC inverter.
To understand the general specification of each component.
To understand the meaning of terms.
Material:
Trainees textbook
Method:
Lecture
Lead over:
Specification
Category
Description
Remarks
HCU
32 bit MICOM
Controls driving power distribution
Inverter
Motor
Maximum 245A (650V/400A power module)
Controls motor torque
HSG
Maximum 125A (650V/200A power module)
Controls HSG torque
LDC
Nominal 1.8kW, Outputs 13.9V
Supplies 12V to vehicle electric devices, modules
Charge the auxiliary battery
Package
Installed location: engine room
Total volume : about 9.2 liter
Total weight : 12.5 kg
HPCU
※ MCU vs Inverter
LDC
MCU
HCU
Inverter (HSG)
Inverter (Motor)

4. Main components of InverterBE
Main components of inverter
Capacitor
The capacitor is a form of auxiliary electricity storage device. It stores electricity during normal conditions and assists the power when voltage is unstable. A maximum of 600V, or approximately 600 μF capacitor is applied. With such capacitor back-up, it takes some time before power depletion is complete, even when the high voltage battery is removed (when the safety plug is removed).
In the case of TF HEV, it takes a maximum of 2 minutes for the battery to fall below 60V after the removal of the safety plug.
Current Sensor
The current sensor detects the electric current flowing to the motor and is used to control the current phase flowing into the motor from the motor controller. The sensors for the motor and for the HSG are different, and the current sensor is internally connected to the power module.
Control Board
One CPU controls 2 motors (the traction motor and HSG motor). In addition to the basic function of motor control, the control board has supplementary features of protecting the motors, inverter and power module from overheating, preventing reverse rotation, detecting failure, and providing a motor temperature compensation circuit.
Power Module
It converts DC power to AC due to the high speed switching. Capacities of 400A are used for the traction motor and 200A for the HSG respectively.
Heat Sink
The heat sink is a heat shield device. A water cooling system is utilized for the HPCU, and an aluminum heat sink is used to maximize the cooling effect.
Each of the components in the diagram is illustrated to help understand the internal structure. It is actually assembled with a liquid gasket so it cannot be taken apart.
To know the internal structure and layout of inverter
Material:
Trainees textbook
Method:
Lecture
Lead over:
Main components of Inverter
Power module
Control board
Capacitor
Heat sink
Control signal
for power module
Max. 600V
Current sensor
Bus bar
Inverter
500A (Motor) 300A (HSG)

5. Converter vs. Inverter BE Converter vs. Inverter
In a hybrid vehicle with continuous discharging and recharging of the battery, it is important to understand the concept of an inverter and a converter.
Converter vs. Inverter
They are both devices that change the characteristics of electricity. Inverters have been widely in use to operate various actuators (particularly motors) in conventional vehicles. Some SUV vehicles are equipped with an AC socket to plug in general electric devices, and these vehicles have an inverter that transforms the DC 12 V to AC 110 V. But in the case of hybrid vehicles, the inverter or converter is directly related to the vehicle driving and safety factors. And because a high voltage battery is used for input power, the inverter or converter is applied with the latest cutting-edge technology, unseen in conventional inverters or converters, to ensure reliability, precision and quality.
DC-AC Converter
It is also called an inverter. The inverter installed in the TF Optima HEV also falls into this category. The inverter receives DC power and converts it to AC power that has variable voltage and frequency. It supplies the converted energy to a 3-phase motor. It is an essential device for controlling the motor RPM and torque.
DC-DC Converter
The LDC installed in the TF Optima HEV falls into this category. As both the input and output are direct current, it is also called a DC converter. As previously mentioned, the LDC also recharges the auxiliary battery, but note that in general, only direct current (DC) can be stored into the battery.
To understand the difference and role of inverter and converter
Material:
Trainees textbook
Method:
Lecture
Lead over:
Converter vs. Inverter
It changes the characteristics of electricity.
Classification of converters
Category
Description
Input
Output
AC-DC converter
Rectifier or PWM converter
AC (commercial) DC
DC-AC converter
Inverter
Alternated V,F
DC-DC converter
DC converter or DC chopper
DC (Vol. up or down)
AC-AC converter
AC voltage controller AC
※ V: Voltage, F: Frequency
Function of inverter:
A device to change DC power source into ‘alternated voltage and frequency’.

6. Protection / Fault diagnosisBE
Inverter functional block diagram
The block diagram above is an illustration to facilitate the understanding of the concept of general functions of an inverter. Therefore, while describing the overall concept, in-depth details were omitted.
The A, B, D, and E sections in the above illustration signify the output signal to other control devices from the inverter and the C signify the input signal to the inverter.
A: The temperature information detected through the internal temperature sensor of the motor is sent to the motor overheat protection circuit and the motor torque control circuit of the inverter. At the same time, the temperature information is transmitted to other control units. The inverter temperature is detected through the internal temperature sensor of the power module and if the temperature is higher than the threshold levels, then the inverter overheat protection circuit activates. This information is also transmitted to other control units. (For example, even though the engine is off, if the inverter temperature exceeds the threshold level, the cooling fan may turn on through command by the inverter.) Lastly, the voltage value of the high voltage battery is also detected by the inverter and is transmitted simultaneously to the motor torque control circuit, self-diagnosis/protection circuit, and other control unit.
B: If a motor torque needs to be limited due to the motor, inverter, or power module overheat or failure, then such information is transmitted to the motor control circuit. At the same time, the information is transmitted to other control units.
C: The control mode, torque command and speed command information from other control units are transmitted to the motor control circuit.
D: The current target motor torque value computed by the inverter is transmitted to the other control units.
E: The inverter receives the actual current speed of the motor from the resolver within the motor and transmits the information to other control units.
To understand the internal and external interface of inverter
Material:
Trainees textbook
Method:
Lecture
Lead over:
Inverter functional block diagram
Inputs (C) : via CAN Control mode, Torque command, Speed command
Inverter (MCU) A
Aux. Battery
Outputs : via CAN A: Motor temperature, DC voltage, Inverter temperature
B: Torque limit
D: Estimated torque
E: Actual motor speed
Protection / Fault diagnosis B
High voltage Battery
Power module + - C
Motor control
Motor
Current sensing D
Speed detector E
Resolver

7. Inverter I/O diagram MCU/GCU (Inverter) BE Inverter I/O diagram IGBT
To operate the control units (MCU, GCU), the auxiliary battery power and the body ground are connected. Therefore, when the auxiliary battery is discharged, the control units cannot operate. As a result, the motor and the HSG cannot operate properly. Dual CAN is used for communication between the control units. The chassis CAN is used to connect the electric water pump for cooling the HPCU.
The orange color high voltage cable that connects the motor and the HSG is the path for recharge and discharge, depending on driving conditions. Each cable is supported with an error code that detects an open circuit. In addition, the terminal related to the resolver and temperature sensor is connected to the inverter by a signal connector. The air conditioning compressor is also operated at high voltage which is supplied from the battery through the inverter. The following picture shows the location and connection path of the high voltage cable and the signal connector which are connected to the HPCU.
To understand the inputs and outputs of Inverter (MCU,GCU)
Material:
Trainees textbook
Method:
Lecture
Lead over:
Inverter I/O diagram
LDC 10A
MCU/GCU (Inverter)
Signal connector
Motor
Aux. battery
Resolver sensor
Vehicle front
To motor
To HSG motor
From high voltage battery
To A/C compressor
Inverter signal connector
LDC
Ignition (IG1)
Temp. sensor
Hybrid CAN
IGBT
Motor control
Chassis CAN
HSG control
EWP
Signal connector
High voltage battery
Resolver sensor
HSG
A/C compressor
Temp. sensor

8. MCU connector configuration (Inverter signal connector)BE
MCU I/O specification
The table lists the MCU input signal values. All base values are analog signals. Refer to the following table for connections between the MCU (inverter) and the motor, HSG, and the high voltage battery.
To understand the input and output specification of motor control unit
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
Pin
Description
A/D/PWM/CAN
Level
VBATT+
High voltage DC positive input DC
200~324V
VBATT-
High voltage DC negative input - 0V MU
Motor U phase output
PWM
0~324V MV
Motor V phase output MW
Motor W phase output HU
HSG U phase output HV
HSG V phase output HW
HSG W phase output
MCU/GCU I/O specification
MCU connector configuration (Inverter signal connector)
PIN
PIN-NAME
FUNCTION
CONNECTION
LEVEL
Remarks 1 TM
MOTOR TEMP SENSOR SIG
MOTOR TEMP SENSOR
0~5V
Input signals (Analog) 4
M_REZS1
MOTOR RESOLVER SENSOR 5
M_REZS2 12
M_REZS3 13
M_REZS4 17 TI
HSG TEMP SENSOR SIG
HSG TEMP SENSOR 20
I_REZS1
HSG RESOLVER SENSOR 21
I_REZS2 28
I_REZS3 29
I_REZS4 33
VB3
BATTERY POWER SUPPLY
12V BATTERY
0~18V 34
IGN
KEY INPUT 36
VB2 38
VB1 3
M_REZ+
0~14V
Output signals (Analog) 11
M_REZ- 19
I_REZ+
1~7V 27
I_REZ-

9. Typical problems of inverterBE
Typical problems of inverter
The above table is a summary of the typical source and symptoms of inverter problems that may occur.
1) Communication Function
Inverter (MCU) is connected to the other control units via Chassis-CAN and Hybrid CAN. In the event of CAN communication failure and the inverter cannot receive any information or commands from the HCU, the HCU determines the condition as ‘HEV NOT READY’. It prevents the vehicle from operating for the driver’s safety. Inspect the connector on the inverter and measure the vertical resistor of the CAN communication line. In addition, use the diagnosis device to check if CAN-related DTC is stored in memory.
2) Measuring DC Voltage
As previously mentioned, the voltage value of the high voltage battery is first measured by the inverter and used for the motor control circuit. At the same time, the information is transmitted to the HCU. If the high voltage cable connection is faulty, or in case of battery relay operation failure, then the voltage cannot be measured. In such case, pre-charge is not possible and it results in unstable torque control. First inspect the connector to ensure proper connection. After pre-charge, use a diagnosis device to compare the voltage of the battery pack and the inverter DC input voltage value.
3) Measuring Rotor Position
If the connection of the position sensor’s signal connector is faulty, or the initial off-set adjustment of the position sensor is omitted, the motor torque control of the inverter becomes unstable. Inspect the connector status and conduct off-set adjustment of the position sensor.
4) Measuring Motor Temperature
If the connection between the inverter and motor is faulty, the inverter output will be limited.
5) Output Performance
If the cooling performance of the HPCU is not normal, the inverter, motor and HSG may overheat. Inspect the HPCU coolant level or check the EWP operation conditions.
To know the typical problems of inverter
Material:
Trainees textbook
Method:
Lecture
Lead over:
Typical problems of inverter
Items
Sub-items
Probable causes
Phenomenon
Function
1) CAN Communication
connection fault of signal connector
non-defined CAN ID used
error frame because of the fault in communication line
torque control impossible
- engine start impossible
- EV mode impossible
2) High DC voltage measurement
connection fault of high voltage DC connector
high voltage battery relay fault
pre-charge impossible
torque control unstable
3) Rotor position measurement
offset calibration not carried out for resolver initial position
signal line fault
4) Motor temperature measurement
output power of inverter limited
Perfor-mance
5) Output performance
inverter over temperature
Motor/ HSG over temperature

10. Definition of LDC functionBE
Definition of LDC function
In general, a converter is a device that transforms DC voltage to another form of voltage. For example, it can transform 100V, 5A input power to 50V, 10A of equal energy (500W).
The circuit on the above right shows the downing of 100V input voltage to 50V using a DC-DC converter.
If a variable resistance is installed in the center of the circuit (in the second circuit), 50V can be achieved. However, it also shows that half of the input energy is lost due to the variable resistance.
In an environmentally friendly vehicle that places high importance on fuel efficiency, such loss must be minimized.
In the final circuit, an appropriate coil (inductance) and a capacitor are installed in the center. When switch ‘A’ indicated in the illustration is opened or closed, the output voltage can be controlled and the energy loss is minimized.
To understand the fundamental operating principle of converter
Material:
Trainees textbook
Method:
Lecture
Lead over:
Definition of LDC function
Function of converter : A device to convert the particular level of voltage into other level
A sample of converting :
DC 100V
DC 5A
500W
DC 50V
DC 10A
Switch “A”
DC 280V
DC 6.5A
1.8KW
DC 13.8V
DC 130A
1.8KW
[ case of TF HEV ]

11. LDC (Low voltage DC-DC Converter)BE
Role of LDC
The alternator in a conventional vehicle is mechanically connected to the engine. If the engine stops, 12V electrical power cannot be supplied. In addition, alternators characteristically lose output when the surrounding temperature increases.
The LDC system in TF Optima HEV is electronically connected to the high voltage battery, so the 12V electric power is supplied whenever electrical components require power, regardless of the engine operation status. In addition, the LDC system maintains stable power output, even when the surrounding temperature increases.
Since the LDC system is not mechanically connected to the engine, there is no friction loss caused by the belt drive.
To understand the role of LDC
Material:
Trainees textbook
Method:
Lecture
Lead over:
Role of LDC
Conventional vehicle
TF Optima HEV
Engine
Engine
Motor
Inverter
Main battery
12V
Battery
ALT
12V
Battery
LDC
Alternator
LDC (Low voltage DC-DC Converter)
Input
Engine (mechanical connection)
Main battery (electrical connection)
Output
12V battery/12V load ←
Function
12V battery charge/12V load supply
Energy flow
Engine  ALT.  12V load
Engine  Drive motor/Inverter  Main battery  LDC  12V load
Characteristic
- Idle stop: impossible to supply 12V
- Temperature: output degraded with ambient temperature rise
- Auto stop: possible to supply 12V
- Temperature: constant power output

12. Current converting flow in LDCBE
Current converting flow in LDC
The above diagram illustrates the concept of how DC voltage is downed by the LDC. It is not directly related to vehicle maintenance and is shown only for reference purposes.
Input Filter
The input filter is a circuit with an embedded capacitor. It detects high voltage DC from the high voltage battery.
MOSFET
When a voltage is detected on a similar high-speed switching circuit to the inverter IGBT, DC is changed to AC. In this respect, the function is almost the same as the function of an inverter (DC  AC). Then the transformer circuit, rectifier circuit and output filter are added and the LDC circuitry is much more complex.
Transformer Circuit
The voltage is downed internally within the transformer by the first and second coil. The high voltage and low voltage is electrically insulated by the transformer. (The first coil shields the 270V while the second coil shields the 12V.)
Rectification Circuit
The AC power is adjusted to specification amplitude as it passes through the diode.
Output Filter
As the wave form is smoothed, the AC power property transforms to DC power.
To understand the current converting flow of LDC
Material:
Trainees textbook
Method:
Lecture
Lead over:
Current converting flow in LDC
B(+)
Vo(+)
Aux. battery
High voltage battery
Vo(-)
B(-)
Filter (input)
MOSFET
Transformer
Diode (rectifier)
Filter (output)
Output DC AC AC AC DC

13. Control/Sensing circuit Transformer/ InductorBE
Main components of LDC
The input power from high voltage battery and the output power of 12V are separated as they are electrically shielded from each other. High voltage DC power cannot be directly converted to low voltage DC power. It must be first converted to AC power and then transformed to DC power. A transformer is used when converting AC power to DC power. This process separates high voltage and low voltage. This separation achieves system stability.
Heat Sink
The heat sink installed on the converter is an air cooling device. It is used to cool the LDC.
Control / Sensing Circuit
The PWM control chip and current sensor are applied.
Snubber / Capacitor
An electric device is applied to protect the power module.
To understand the component layout of LDC
Material:
Trainees textbook
Method:
Lecture
Lead over:
Main components of LDC
Control/Sensing circuit
Heat Sink
Noise Filter
Output Diode
Controller
control signal
Converter
Snubber / Capacitor
Transformer/ Inductor
Power module (MOSFET)

14. LDC I/O diagram LDC BE LDC I/O diagram LDC power output MOSFET LDC 10A
As previously mentioned, to charge the auxiliary battery with high voltage from the high voltage battery, approximately 12V of DC power is variably output. This output terminal is connected in parallel to the auxiliary battery as illustrated in the diagram so that the LDC output power can be directly used to operate the vehicle’s electrical components. The LDC is only connected to the chassis CAN. It is not connected to Dual CAN.
To understand the inputs and outputs diagram
Material:
Trainees textbook
Method:
Lecture
Lead over:
LDC I/O diagram
LDC 10A
LDC
Aux. battery
Chassis CAN
LDC power output
LDC signal connector
Ignition (IG1)
MOSFET
High voltage battery
HCU signal connector
HPCU ass’y

15. Aux. battery temperature sensorBE
Variable voltage control
Purpose
Electrical load in a vehicle is not always constant. It changes constantly based on the driving conditions and the driver’s intentions. As is in a conventional vehicle, using only the necessary voltage for a vehicle’s electrical load reduces the vehicle’s total electricity consumption. Continuously outputting unnecessarily high voltage wastes battery energy. This will ensure higher fuel efficiency.
The hybrid vehicle is very sensitive to fuel economy and it demands attention to achieve even small improvements in fuel efficiency (about 1.3%). Accordingly, even though the LDC receives a command from the HCU to output electrical power, the LDC variably controls the voltage based on the driving conditions. This is called ‘variable voltage control’. In other words, the LDC output is controlled to prevent overcharging of the auxiliary battery and this result in enhanced HEV driving performance while improving fuel efficiency.
Overview
There is a maximum and minimum limit on the voltage output by the LDC and the output changes depending on the vehicle’s driving conditions. If the LDC cannot receive command from the HCU as a result of CAN communication failure, then the LDC outputs a fixed amount of voltage (e.g., 13.5V).
Strategy
Stopped: Outputs highest level of voltage to charge the auxiliary battery.
Acceleration: When accelerating in EV Mode, the auxiliary battery is discharged and the LDC outputs minimum voltage
Cruising: Auxiliary battery is charged if in HEV mode with the engine operating. Auxiliary battery is discharged and the LDC outputs minimum voltage if in EV mode.
Deceleration: The high voltage battery is charged via regenerative braking, and the auxiliary battery is charged with the rated-voltage output from the LDC.
Engine auto stop: The auxiliary battery is discharged but minimum and maximum voltage amount is repeatedly outputted by the LDC to prevent over discharging of the auxiliary battery.
The values in the following parenthesis are reference values only to facilitate understanding of the concept. The actual values on the final design of the production model may change. (High: 14.1V, Middle: 13.9V, Low: 12.8V)
※ Conditions that prevent LDC Variable Control: When using specific electrical devices (headlamp / wiper / blower max, etc.) or when the outside temperature is below 0℃.
Temperature Sensor
For effective recharging of the auxiliary battery that was discharged during voltage control, a temperature sensor was added to detect the temperature of the auxiliary battery. Without such temperature sensor, overcharging of the auxiliary battery may occur and it may cause electrical problems in the vehicle. The added temperature sensor has the same specifications as the ambient temperature sensor used in the FATC. The temperature data goes through the BMS and to the HCU. The auxiliary battery’s temperature value is adjusted by the HCU’s internal logic and transmits the optimal voltage output to the LDC. The temperature sensor is assembled on the upper section of the auxiliary battery mounting bracket.
To understand the objective of variable voltage control
To understand the operating strategy of voltage control in LDC
Material:
Trainees textbook
Method:
Lecture
Lead over:
Variable voltage control
Strategy
Stop
Acceleration
Cruising
Deceleration
Auto stop
Aux. Battery status
Charging
Discharging
Charging
Discharging
Charging
Discharging
Engine running
High
LDC output voltage
Mid.
Low
Data flow
Temperature correction
Voltage control command
CAN
CAN
Aux. battery temperature sensor
BMS
HCU
LDC

16. Typical problems in LDCBE
Typical problems in LDC
The above table is a summary of the typical source and symptoms of LDC problems that may occur.
1) Communication Function
LDC is connected to the other control devices via Chassis-CAN. If a CAN communication failure occurs, variable voltage control by the LDC is not possible and the LDC outputs a fixed voltage amount (13.5V). Inspect the connector on the LDC and measure the vertical resistor of the CAN communication line. In addition, use the diagnosis device to check the CAN related DTC stored to memory.
2) Measuring DC Voltage
The LDC operates on power supplied by the high voltage battery, so the high voltage input line is constantly monitored. In such case, pre-charge is not possible and it results in unstable output voltage control by the LDC. First, inspect the LDC high voltage line connector to ensure proper connection. Then, after pre-charge, use a diagnosis tool (service data) to compare the voltage of the battery pack and the LDC DC input voltage value.
3) Output Performance
The LDC may overheat if the HPCU cooling does not operate properly, and as a result, the LDC output may be limited. Inspect the HPCU coolant level or check the EWP operation conditions. As the LDC output is limited, inspect the auxiliary battery for discharge.
To know the typical problems of LDC
Material:
Trainees textbook
Method:
Lecture
Lead over:
Typical problems in LDC
items
Sub-items
Probable causes
Phenomenon
Function
1) CAN communication
connection fault of signal connector
non-defined CAN ID used
error frame because of fault in communication line
variable voltage control is impossible
cannot charge aux. battery
2) High DC voltage measurement
connection fault of high voltage DC connector
pre-charge impossible
LDC output voltage is unstable
Perfor-mance
3) Output performance
output power limited
LDC over temperature
LDC over-load

17. Engine coolant reservoir Engine coolant reservoirBE
HPCU cooling system
Various semiconductor devices are utilized within the HPCU (the core component for controlling the hybrid vehicle), and these devices generate unavoidable heat when in operation. These devices are directly linked to high voltage, so their heat level is higher than the electrical devices found in a conventional combustion engine vehicle. Overheating lowers the efficiency of the control devices and limits proper operation control. In addition, the semiconductor can melt in extreme high temperatures (the devices are always turned ON) and such overheating causes failure.
Therefore, it is very important to properly cool the HPCU related components. For this purpose, the TF Optima HEV has a supplementary water cooling line in addition to the existing engine cooling line. The reason the system does not share the engine cooling line is because it is not possible to use the same cooling line for both systems because the temperature for the cooling section of the mechanical combustion chamber is significantly different to the temperature for the cooling section of the high voltage semiconductor components. For example, the engine coolant sets the overheat temperature as 100℃, but the HPCU limits the normal operating temperature at 75℃.
When examining the effects of temperature on the inverter more closely, the inverter outputs about 80% of rated output at 75℃, and its output starts to be significantly limited at 90℃. When the temperature reaches 95℃, the inverter output is shut down.
LDC is even more sensitive to high temperature. It outputs 100% of the rated output up to 65℃, but it becomes limited to about 60% at 75℃, then down to 25% at 80℃. The LDC output shuts down completely at 85℃.
For more detailed information, refer to the DTC Service Data section in later in this manual.
An electric water pump is newly added to circulate the coolant. It is directly operated by the MCU. As shown in the diagram, the additional cooling line also cools the HSG. Because it is independent from the engine cooling line, a separate coolant reservoir tank is needed and the tank is mounted near the HPCU.
To understand the necessity and layout of HPCU cooling system
Material:
Trainees textbook
Method:
Lecture
Lead over:
HPCU cooling system +
Engine coolant reservoir
Engine coolant reservoir
Added reservoir
Reservoir
Inlet hose
Electric water pump
Inlet hose
Outlet hose
To radiator
Outlet hose

18. Electric Water Pump BE Electric water pump Inverter (MCU) EWP
The electric water pump weighs about 1kg. It has a CAN communication circuit embedded and it is connected to the vehicle’s chassis-CAN. It is mounted at the RH section of the engine room (near the HSG). The EWP has a 3-phase motor, and like other motors, the hall sensor is embedded within the motor. (Hall sensors 1,2, and 3)
To know the general feature of electric water pump for HPCU cooling
Material:
Trainees textbook
Method:
Lecture
Lead over:
Electric Water Pump
Chassis CAN
EWP
HSG
EWP
Inverter (MCU)
Stator Assembly
Rotor Assembly
Driver Cover
Impeller
Pin
Description 1
CAN - Low 2
CAN - High 3
Ground 4 B+
Body Pump
Cover Pump

19. EWP operation BE EWP operation Mode Sequence Condition Normal mode
During normal operation of the system, the MCU determines the activation of the EWP based on the vehicle’s coolant temperature. If the temperature of the HPCU assembly (detected by the temperature sensor on the power module base plate in the HPCU) is above 45℃, or the coolant temperature (temperature of the HPCU cooling line, not the coolant temperature of the engine) is above 35℃, the MCU activates the EWP via the CAN communication line. At this time, the motor speed is set to 3,300 RPM. (The motor speed is always set to 3,300 RPM in Motor ON condition.)
The condition for turning the EWP off is when the HPCU assembly temperature and the coolant temperature fall below 40℃ and 30℃, respectively.
EWP Error Mode
The EWP self diagnoses its error status and sends the information to the MCU. In the event of EWP failure, the MCU sends a request to the cluster to turn on the service lamp, and EWP related DTC is stored in memory. The following are the EWP controls for each error condition:
- Failure of the hall sensor within the motor (short circuit) or disconnection/short circuit of the motor’s 3-phase circuit: EWP motor is stopped.
- EWP is normal but failure in CAN communication: EWP motor is operated at its rated speed (3,300 RPM)
There is only 1 error code for EWP related error:
- P0C73 (control performance of motor electronics coolant pump)
In case of hall sensor or FET, motor coil disconnection, short circuit or overheating (above 160℃), only one error code for any of the failures is displayed and stored in the MCU.
If the EWP fails, there is the potential that the HPCU and the HSG will overheat or become damaged. Therefore, the motor and the HSG torque are limited.
Coolant Refill Mode
When refilling the coolant in the cooling system of a hybrid vehicle, use a diagnosis device to force operate the EWP and conduct air bleeding. Please refer to the next page for a detailed procedure.
To understand the operating sequence as well as the behavior in diagnostic mode
Material:
Trainees textbook
Method:
Lecture
Lead over:
EWP operation
Mode
Sequence
Condition
Normal mode
EWP ON : HPCU temp. 45℃ ↑ OR Coolant temp. 35℃ ↑
EWP OFF :
HPCU temp. 40℃ ↓ AND Coolant temp. 30℃ ↓
EWP failure mode
1: No failure, 0: Failure
When EWP is failed, Service lamp in the cluster is turned on by MCU and DTC is stored in MCU.
Coolant add mode
Need to drive EWP by GDS when you add coolant ON
HPCU temp.
OFF
EWP
Coolant temp.
MCU 1
EWP
MCU
Cluster
EWP
GDS
MCU ON
IG key status
OFF
EWP enable (‘1’)
CAN command signal (MCU  EWP)
EWP disable (‘0’)
3,300 rpm
EWP motor speed
0 rpm
▽t ≤ 5 sec
EWP status signal via CAN (EWP  MCU)
Normal mode
EWP failure mode

20. Air bleeding of HPCU cooling lineBE
Air bleeding of HPCU cooling line
When exchanging or repairing the HSG, HPCU or EWP, use the diagnosis device upon completion to conduct air bleeding of the line.
The specifications for the HPCU coolant are not much different to the engine coolant (water 50-60%, glycol 40-50%), but if specifications are not complied with, it may result in corrosion of the aluminum heat sink, or the coolant path may be clogged by the sediments.
The following are the procedures for refilling the coolant and air bleeding:
Add coolant into the reservoir tank
Connect “GDS Tool” to diagnosis connector.
Follow the “GDS” screen to perform the coolant adding
Add coolant so that the coolant level is kept between “Low” and “High” level.
If EWP operate without a sufficient amount of coolant for approximately 5 seconds, the protect function will activate to stop the EWP for about 15 seconds. If a sufficient amount of coolant is added, EWP will start operating automatically.
When the operational sound volume of the EWP becomes small or when no air bubbles can be seen in the reservoir tank, bleeding of the coolant system is completed. (It would take about minutes)
After bleeding is completed, stop the EWP, add coolant to the “Full” level, and install the reservoir cap.
* NOTICE :
Make sure to add more coolant than was drained initially.
To be able to do an air bleeding in HPCU cooling circuit.
Material:
Trainees textbook
Method:
Lecture
Lead over:
Air bleeding of HPCU cooling line
① Add coolant
② Connect GDS
③ Move to the menu of Vehicle S/W :
Engine stop, IG ON
No DTC (P0C73)
④ Coolant level
⑤ Air bleeding (3min.)
⑥ Stop EWP, add coolant more
High
Full
Low

21. Air bleeding of HPCU cooling lineBE
Air bleeding of HPCU cooling line
This function is used for removing excessive air from adding water in the water coolant in hybrid vehicles after repairing HSG/HPCU or repairing related EWP in electric water pump. Condition: Ignition on and engine stop No DTC exists (e.g EWP related trouble code, P0C73; EWP performance error, No MIL turns on) After adding water in the water coolant, press ‘OK’ button.
Electric water pump actuation must be completed in 3 minutes. To stop the process during EWP actuation, press ‘Cancel’ button. You can check the elapsed time in the scanner.
Electric water pump actuation is completed. Check for surge inside reservoir. Retry EWP actuation after 30sec until no air surge is found.
To be able to do an air bleeding in HPCU cooling circuit using the instructed menu in the scanner.
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
Air bleeding of HPCU cooling line

22. Current Data - MCU BE MCU / GCU (Inverter) service data
The definition of the GCU-related service data supported by the diagnosis tool and the diagnosis procedure are detailed as follows:
Main Relay Cutoff Request Flag by the MCU
It shows the cutoff request of high voltage main relay. If the status is ON, then the request is made. In this status, a failure in which the high voltage relay needs to be cutoff from the MCU has occurred and the motor cannot be operated.
Capacitor Voltage
It displays the input DC-link capacitor voltage of the inverter or the MCU/GCU. If the main relay is OFF during initial engine start, a value closest to zero (0) is displayed. If the main relay is ON and there is no input or output of motor power, then the value equal to the battery voltage value will be indicated.
Motor Controllable Flag
The motor controllable flag displays whether or not the motor is in operable state. The status is maintained as OFF if ignition key start does not turn on, the auxiliary battery (12V) voltage is low, high voltage is not connected, or MCU failure occurs.
MCU Ready Flag
The MCU ready flag indicates that the MCU is ready for operation. If the MCU is ready for operation after the ignition is turned on, then ON is displayed and the MCU communicates signals with other control units. If OFF is displayed, then EV Mode is not available. But the engine can still be started via GCU. (However, the engine can only be started via GCU if high voltage is connected and ‘Ready’ and ‘Controllable flag’ of the HSG control unit (GCU) are on.
MCU Service Lamp ON Request Flag
The MCU Service Lamp ON Request Flag is the request to turn on the lamp to alert the driver of MCU or motor failure. In general, EV mode is not available when the service lamp is on, but if the ON is caused by disconnection / short circuit of the temperature sensor, then limited EV Mode driving is possible.
MCU MIL ON Request Flag
If MCU or motor failure that can affect the emission performance occurs, then the MIL lamp ON is requested in accordance with OBD regulation. If the same failure occurs consecutively for 2DC (Driving Cycle), then the indicator lamp turns on. If the same failure does not occur for 3DC, then the MIL lamp ON request is cancelled.
Motor Actuation Test Flag
The motor actuation test flag is to prevent other master control unit activates the motor when forced operation of the motor is engaged. If the motor actuation (torque control, speed control) and supplementary function (resolver offset calibration) is engaged, the actuation test flag is turned on to alert the other control units.
MCU Warning Flag
The MCU warning flag is an alert signal that indicates MCU warning and shows that power limited drive is engaged. If the indication is ON, then ‘power limited EV Mode’ is possible.
MCU Fault Flag
If a failure in the MCU or the motor occurs, and normal operation is not possible, the fault flag indicates ON and alerts other control units.
MCU Temperature
It displays the detected temperature value of the IGBT base plate of the MCU. The rate of temperature increase becomes greater as the MCU output increases. If the MCU temperature reaches above 90℃, power-output-limited driving is engaged, and if the temperature exceeds 95℃, then the output torque becomes zero.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
Current Data - MCU

23. MCU / GCU (Inverter) service dataBE
MCU / GCU (Inverter) service data
The definition of the GCU-related service data supported by the diagnosis tool and the diagnosis procedure are detailed as follows:
Main Relay Cutoff Request Flag by the MCU
It shows the cutoff request of high voltage main relay. If the status is ON, then the request is made. In this status, a failure in which the high voltage relay needs to be cutoff from the MCU has occurred and the motor cannot be operated.
Capacitor Voltage
It displays the input DC-link capacitor voltage of the inverter or the MCU/GCU. If the main relay is OFF during initial engine start, a value closest to zero (0) is displayed. If the main relay is ON and there is no input or output of motor power, then the value equal to the battery voltage value will be indicated.
Motor Controllable Flag
The motor controllable flag displays whether or not the motor is in operable state. The status is maintained as OFF if ignition key start does not turn on, the auxiliary battery (12V) voltage is low, high voltage is not connected, or MCU failure occurs.
MCU Ready Flag
The MCU ready flag indicates that the MCU is ready for operation. If the MCU is ready for operation after the ignition is turned on, then ON is displayed and the MCU communicates signals with other control units. If OFF is displayed, then EV Mode is not available. But the engine can still be started via GCU. (However, the engine can only be started via GCU if high voltage is connected and ‘Ready’ and ‘Controllable flag’ of the HSG control unit (GCU) are on.
MCU Service Lamp ON Request Flag
The MCU Service Lamp ON Request Flag is the request to turn on the lamp to alert the driver of MCU or motor failure. In general, EV mode is not available when the service lamp is on, but if the ON is caused by disconnection / short circuit of the temperature sensor, then limited EV Mode driving is possible.
MCU MIL ON Request Flag
If MCU or motor failure that can affect the emission performance occurs, then the MIL lamp ON is requested in accordance with OBD regulation. If the same failure occurs consecutively for 2DC (Driving Cycle), then the indicator lamp turns on. If the same failure does not occur for 3DC, then the MIL lamp ON request is cancelled.
Motor Actuation Test Flag
The motor actuation test flag is to prevent other master control unit activates the motor when forced operation of the motor is engaged. If the motor actuation (torque control, speed control) and supplementary function (resolver offset calibration) is engaged, the actuation test flag is turned on to alert the other control units.
MCU Warning Flag
The MCU warning flag is an alert signal that indicates MCU warning and shows that power limited drive is engaged. If the indication is ON, then ‘power limited EV Mode’ is possible.
MCU Fault Flag
If a failure in the MCU or the motor occurs, and normal operation is not possible, the fault flag indicates ON and alerts other control units.
MCU Temperature
It displays the detected temperature value of the IGBT base plate of the MCU. The rate of temperature increase becomes greater as the MCU output increases. If the MCU temperature reaches above 90℃, power-output-limited driving is engaged, and if the temperature exceeds 95℃, then the output torque becomes zero.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
MCU / GCU (Inverter) service data
Item
Description
Unit
Phenomenon
MCU
Main relay cutoff request flag by MCU
The status of high voltage main relay cut off request status
ON/OFF
ON: main relay off condition, EV/HEV mode is impossible, failsafe driving by engine running
Capacitor voltage
200~310V (main relay ON) Lower than 180V (fault) Higher than 380V (fault) V
EV mode impossible and engine cannot be started by neither motor nor HSG.
Motor controllable flag
ON: inverter, motor is controllable OFF: motor stops
EV mode prohibited.
Engine can be started by HSG/GCU as long as high voltage power is connected.
MCU ready flag
ON: MCU is ready to operate OFF: MCU is not ready to operate
EV mode prohibited, engine can be started by HSG/GCU under ‘OFF’ condition .
MCU service lamp ON request flag
ON: fault in MCU or motor OFF: MCU & motor is OK
EV mode prohibited (except temp. sensor open/short circuit : power limited), engine can be started by HSG/GCU
MCU MIL on request flag
ON: requests MIL on to ECU
OFF: does not request MIL
Motor actuation test flag
ON: motor actuation test is operating -
MCU warning flag
ON: motor torque is limited OFF: MCU or motor is OK
EV mode is possible but motor torque is limited, engine starts by HSG/GCU
MCU fault flag
ON: MCU and motor stops OFF: MCU & motor is OK
EV mode is impossible (as long as ‘ON’), engine starts by HSG/GCU
MCU temperature
Normal range: -30~150℃ Inverter temp. sensor fail: 214℃ ℃
EV mode is limited or impossible if MCU is overheat but engine can be started by HSG.

24. MCU / GCU (Inverter) service dataBE
MCU / GCU (Inverter) service data
Aux. Battery Voltage
Aux. battery voltage indicates the auxiliary battery output voltage. If the LDC is in normal operation, then the indicated value is equal to the LDC output voltage.
Actual Motor Speed
Actual motor speed is the value computed by using the motor position sensor output value. If the engine clutch is active, then it synchronizes with the engine speed. In general, the motor RPM is 40% of the HSG RPM. If sensing is not possible due to failure of the motor position sensor, then the output value is indicated at 32,768 RPM.
Motor Torque Reference
Motor torque reference displays the torque command value that the motor must output as the result of torque distribution logic in the HCU. The maximum value of the torque command decreases as the vehicle speed increases. Higher absolute value of the command increases the motor output value.
Actual Motor Torque
Actual motor torque refers to the actual motor torque output.
Motor Phase Current
Motor phase current indicates the level of the current flowing in the motor. If the electric current value is zero at a motor speed of 1,400 RPM, then the motor control is cutoff. Even though the motor control is cutoff, if the vehicle is in high speed, then the electric current value generated by counter electromotive force may be indicated.
Motor Temperature
Motor temperature indicates the coil temperature of the drive motor stator. The rate of temperature increase becomes greater as motor output increases. If the motor temperature reaches above 170℃, power output limited driving is engaged, and if the temperature exceeds 180℃, then the output torque becomes zero.
GCU Ready Flag
The GCU ready flag indicates that the CGU is ready for operation. If the HSG control unit (CGU) is ready for operation after the ignition is turned on, then ON is displayed and the CGU commences to communicate signals with other control units. If OFF is displayed, then EV mode is not available, but the engine can still be started by the MCU. (However, the engine can only be started by MCU if the high voltage is normally connected and ‘Ready’ and ‘Controllable flag’ of the MCU are on.)
GCU Service Lamp ON Request Flag
If failure of the HSG control unit (GCU) or HSG which can affect the emission performance occurs, then the MIL lamp ON is requested in accordance with OBD regulation. If the same failure occurs consecutively for 2DC (Driving Cycle), then the indicator lamp turns on. If the same failure does not occur for 3DC, then the MIL lamp ON request is cancelled.
GCU Warning Flag
If the GCU warning flag indication is ON, it means that a fault in the HSG control unit (GCU) or the HSG has been detected, and power limited driving is engaged.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
MCU / GCU (Inverter) service data
Item
Description
Unit
Phenomenon
Other
Aux. battery voltage
9~16V (MCU normal operation) < 9V or > 16V (MCU control stops) < 6.5V or > 20V (CAN stops) V
If aux. battery voltage < 9V or > 16V,
Neither EV mode nor engine starting is prohibited
Motor
Actual motor speed
Normal: 0~6,500 rpm Same as engine speed as long as engine clutch is engaged 32,768 rpm: motor position sensor failure
rpm
If resolver is failed, EV mode is impossible and engine can be started by HSG.
Motor torque reference
It reduces as the motor speed increases. (e.g. 1,200rpm or less 205Nm, 3,000rpm 95.5Nm) Normal range: -100 ~ 99.8% % -
Actual motor torque
When this value is zero: EV mode is impossible but engine can be started by HSG.
Motor phase current
When motor control stops, it shows zero except high speed. A
Motor temperature
Normal range: -20~200℃ Temp. sensor fail: 214℃ ℃
EV mode is limited or impossible if motor is overheat but engine can be started by HSG.
GCU
GCU ready flag
ON: GCU is ready to operate OFF: GCU is not ready to operate
ON/OFF
EV mode prohibited. Engine can be started by MCU.
GCU service lamp ON request flag
ON: fault in GCU or HSG OFF: GCU & HSG is OK
EV mode prohibited (except temp. sensor open/short circuit : power limited), engine can be started by MCU.
GCU warning flag
ON: Power is limited OFF: GCU or HSG is OK
Even if this value is ON, EV mode is possible by MCU (power limited) and engine can be started by MCU

25. MCU / GCU (Inverter) service dataBE
MCU / GCU (Inverter) service data
GCU Fault Flag
If a failure in the HSG control unit (GCU) or the HSG occurs and normal operation is not possible, the fault flag indicates ON and alerts other control units.
GCU Temperature
It displays the detected temperature value of the IGBT base plate of the GCU. The rate of the temperature increase becomes greater as the GCU output value increases. If the GCU temperature reaches above 90℃, power output limited driving is engaged. If the temperature exceeds 95℃, then the output torque becomes zero.
Actual HSG Speed
Actual HSG speed is computed by using the HSG position sensor (resolver) output value. It has 2.5 times the value of the engine speed and the drive motor speed.
HSG Torque Reference
A higher absolute value of the command will increase the HSG output torque. The maximum value of the torque command will decrease as the vehicle speed increases.
Actual HSG Torque
Actual HSG Torque refers to the HSG torque output.
HSG Phase Current
HSG phase current indicates the level of the current flowing in the HSG. If the electric current value is zero, then the motor control is cutoff. Even though the motor control is cutoff, if the vehicle is in high speed, then the electric current value generated by counter electromotive force may be indicated.
HSG Temperature
HSG temperature indicates the coil temperature of the HSG motor stator. It has a similar pattern to the GCU temperature increase but their level is different. The rate of the temperature increase becomes greater as the HSG output increases. If the HSG temperature reaches above 170℃, power output limited driving is engaged. If the temperature exceeds 180℃, then the output torque becomes zero.
HSG Controllable Flag
The status is maintained as OFF if the ignition key start does not turn on, the auxiliary battery (12V) voltage is low, high voltage is not connected, or GCU failure occurs.
HSG Actuation Test Flag
HSG actuation test flag is to prevent other master control unit activates the motor when forced operation of the HSG is engaged. If HSG actuation (torque control, speed control) and supplementary function (resolver offset calibration) is engaged, the actuation test flag is turned on to alert the other control units.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
MCU / GCU (Inverter) service data
Item
Description
Unit
Phenomenon
GCU
GCU fault flag
ON: GCU and HSG stops OFF: GCU & HSG is OK
ON/OFF
ON: EV mode prohibited. Engine can be started by MCU.
GCU temperature
Normal range: -30~150℃ GCU temp. sensor fail: 212℃ ℃
Even if GCU is overheat, EV mode is possible by motor and engine can be started by motor and engine clutch ‘compulsory lock-up’ engagement.
HSG
Actual HSG speed
Normal: 0~16,500 rpm 32,768 rpm: HSG position sensor failure
rpm
Even if HSG position sensor (resolver) is failed, EV mode is possible by motor and engine can be started by motor and engine clutch ‘compulsory lock-up’ engagement.
HSG torque reference
It reduces as the HSG speed increases. (e.g. 1,200rpm or less 43.2Nm, 3,000rpm 26Nm) Normal range: -100 ~ 99.8% % -
Actual HSG torque
Normal range: -100 ~ 99.8%
Max. torque may reduce as the speed increases.
Even if HSG torque is zero, EV mode is possible by motor and engine can be started by motor and engine clutch ‘compulsory lock-up’ engagement.
HSG phase current
When HSG control stops, it shows zero except high speed. A
HSG temperature
Normal range: -20~200℃ Temp. sensor fail: 212℃
Even if HSG is overheat, EV mode is possible and engine can be started by motor and engine clutch ‘compulsory lock-up’ engagement.
HSG controllable flag
ON: GCU and HSG can be controlled normally. OFF: HSG cannot be controlled.
In case of ‘OFF’, EV mode is prohibited and engine can be started by motor as long as the high voltage is connected.
HSG actuation test flag
ON: HSG motor actuation test is operating

26. MCU / GCU (Inverter) service dataBE
MCU / GCU (Inverter) service data
HSG Resolver Offset
HSG resolver offset displays the mounting deviation of the resolver compared to the initial value when assembled with the HSG. If the mounting deviation exceeds approximately ±11 rad, based on 2.28 rad, then resolver offset calibration is not possible.
HSG Resolver CAL Command
HSG resolver calibration command displays the adjustment function status during offset adjustment of the resolver. If ‘4’ is indicated, then that off-set adjustment of the resolver is not complete, and in this case, normal operation of HSG may not be possible.
HSG Resolver Mal. Counter
HSG resolver malfunction counter indicates the number of error detections by the HSG resolver. Each time an error is detected, the number increases by 1 and it accumulates in the 1DC. The number may increase as a result of resolver malfunction, wire and connector failure, or external shock and noise and if 132 times of error is consecutively detected, and then the resolver failure is confirmed.
 Motor Resolver Off-set
Motor resolver off-set displays the mounting deviation of the resolver compared to the initial value when assembled with the motor. If the mounting deviation exceeds approximately ±11 rad based on 2.28 rad, then resolver off-set adjustment is not possible.
Motor Resolver CAL Command
It Motor resolver CAL command displays the calibration function status during off-set adjustment of the resolver. If ‘4’ is indicated, then off-set adjustment of the resolver is not completed and in this case, normal operation of the motor may not be possible.
Motor Resolver Mal. Counter
Motor resolver malfunction counter indicates the number of error detections of the motor resolver. Each time an error is detected, the number increases by 1 and it accumulates in the 1DC. The number may increase as a result of resolver malfunction, wire and connector failure, or external shock and noise. If 132 times of error is consecutively detected, then resolver failure is confirmed.
Main Relay Cutoff Request Flag by GCU
Main relay cutoff request flag by GCU displays the high voltage main relay cutoff request. If the status is ON, then the request is made and a failure in which the high voltage relay needs to be cutoff from the GCU and the HSG motor cannot be operated while in this status.
GCU MIL ON Request Flag
If failure of the HSG control unit (GCU) or HSG that can affect emission performance occurs, then the MIL lamp ON is requested in accordance with the OBD regulation. If the same failure occurs consecutively for 2DC, then the indicator lamp turns on. If the same failure does not occur for 3DC, then the MIL lamp ON request is cancelled.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
MCU / GCU (Inverter) service data
Item
Description
Unit
Phenomenon
Resolver
HSG resolver offset
Installing tolerance of resolver in HSG motor
Spec: 2.28rad, Tolerance: ±11rad
rad
Resolver offset calibration may not be possible if out of tolerance range.
HSG resolver CAL command
‘0’: calibration completed, ‘1’: calibration failure
‘2’: calibrating, ‘3’: calibration started
‘4’: No calibration was performed -
In case of ‘4’, HSG may not operate.
HSG resolver Mal. counter
Malfunction counter for HSG resolver.
HSG resolver failure will be set if it exceeds 132.
Probable cause: resolver failure, poor wiring or connector, shock or noise
Motor resolver offset
Installing tolerance of resolver in traction motor
Motor resolver CAL command
Motor resolver Mal. counter
Malfunction counter for motor resolver.
GCU
Main relay cutoff request flag by GCU
The status of high voltage main relay cut off request status
ON/OFF
ON: main relay off condition, EV/HEV mode is impossible, failsafe driving by engine running
GCU MIL on request flag
ON: requests MIL on to ECU
OFF: does not request MIL
EV mode prohibited (except temp. sensor open/short circuit : power limited), engine can be started by motor

27. Current Data - LDC BE LDC service data
The definition of the LDC-related service data supported by the diagnosis device and the diagnosis procedure are detailed as follows:
LDC Fault Flag:
It indicates LDC error. If the status is ON, then there is an LDC error. Its output is either limited or stopped.
LDC Service Lamp Request Flag:
The LDC service lamp request flag is the request to turn on the lamp to alert the driver of the LDC failure. If the status is ON, then there is an LDC error.
In case of an LDC-related DTC (P0A94/P0C3A/P0C3B/P1A88/P1A89) occurrence, or if the LDC cannot receive communication from HCU via CAN communication, the service lamp ON request is sent.
LDC Ready Status Flag:
The LDC ready status flag indicates that the LDC is ready for operation. If it is OFF, then LDC is not operating normally. Check the auxiliary battery and LDC status.
LDC Operating Status:
54{>LDC operating status indicates the PWM output status for LDC control. If it is OFF, then PWM is not operating and it signifies that control is terminated. Check to see if the LDC is not operating because of its own error (refer to DTC and LDC fault flag) or if the operating failure is not an LDC error but another source (main relay OFF or termination command from the HCU).
LDC Under Voltage Control Status:
It indicates LDC’s low voltage control status. If it is OFF, then LDC is operating normally. If it is ON, then the LDC is in load status or is operating at low voltage (12.8V) control status due to internal factors. Even if the status is ON, it does not mean LDC malfunctions and the LDC operates normally.
LDC Power Derating Status:
This indicates limited output status of the LDC. If it is ON, the LDC output is limited due to internal failure (overheating, sensor malfunction, etc.).
LDC Output Voltage:
This indicates the LDC output voltage. Operable input voltage must be supplied for proper output voltage.
LDC Output Current:
This indicates the LDC output current. The output current may increase or decrease based on the vehicle’s electrical load. If the output is above 135A, the LDC output is limited, and if it is over 220A, the LDC output will be cut off due to high amperage malfunction.
LDC Input Voltage:
LDC input voltage indicates the DC voltage of the LDC input. The average voltage is 270V under normal operation. In other words, it is equal to the voltage of MCU’s DC-LINK.
LDC Temperature:
LDC temperature is the output value of the temperature sensor mounted on the LDC’s power module (FET, diode). If the temperature sensor is operating normally but the temperature value exceeds the limited value, the cooling system must also be inspected.
To understand the meaning of service data of scanner in LDC system.
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
Current Data - LDC

28. LDC service data BE LDC service data Item Description Unit Phenomenon
The definition of the LDC-related service data supported by the diagnosis device and the diagnosis procedure are detailed as follows:
LDC Fault Flag:
It indicates LDC error. If the status is ON, then there is an LDC error. Its output is either limited or stopped.
LDC Service Lamp Request Flag:
The LDC service lamp request flag is the request to turn on the lamp to alert the driver of the LDC failure. If the status is ON, then there is an LDC error.
In case of an LDC-related DTC (P0A94/P0C3A/P0C3B/P1A88/P1A89) occurrence, or if the LDC cannot receive communication from HCU via CAN communication, the service lamp ON request is sent.
LDC Ready Status Flag:
The LDC ready status flag indicates that the LDC is ready for operation. If it is OFF, then LDC is not operating normally. Check the auxiliary battery and LDC status.
LDC Operating Status:
54{>LDC operating status indicates the PWM output status for LDC control. If it is OFF, then PWM is not operating and it signifies that control is terminated. Check to see if the LDC is not operating because of its own error (refer to DTC and LDC fault flag) or if the operating failure is not an LDC error but another source (main relay OFF or termination command from the HCU).
LDC Under Voltage Control Status:
It indicates LDC’s low voltage control status. If it is OFF, then LDC is operating normally. If it is ON, then the LDC is in load status or is operating at low voltage (12.8V) control status due to internal factors. Even if the status is ON, it does not mean LDC malfunctions and the LDC operates normally.
LDC Power Derating Status:
This indicates limited output status of the LDC. If it is ON, the LDC output is limited due to internal failure (overheating, sensor malfunction, etc.).
LDC Output Voltage:
This indicates the LDC output voltage. Operable input voltage must be supplied for proper output voltage.
LDC Output Current:
This indicates the LDC output current. The output current may increase or decrease based on the vehicle’s electrical load. If the output is above 135A, the LDC output is limited, and if it is over 220A, the LDC output will be cut off due to high amperage malfunction.
LDC Input Voltage:
LDC input voltage indicates the DC voltage of the LDC input. The average voltage is 270V under normal operation. In other words, it is equal to the voltage of MCU’s DC-LINK.
LDC Temperature:
LDC temperature is the output value of the temperature sensor mounted on the LDC’s power module (FET, diode). If the temperature sensor is operating normally but the temperature value exceeds the limited value, the cooling system must also be inspected.
To understand the meaning of service data of scanner in LDC system.
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
LDC service data
Item
Description
Unit
Phenomenon
LDC fault flag
ON: LDC stop to operate OR output is limited. OFF: LDC is OK
ON/OFF
Both EV mode and engine starting are possible
LDC service lamp request flag
ON: LDC fail and operation may stop. OFF: LDC is OK
LDC ready status flag
ON: LDC is OK, check this value is ‘ON’ if LDC is OK.
OFF: LDC is abnormal, check aux. battery and LDC
LDC operating status
ON: LDC outputs PWM normally
OFF: PWM output stops
LDC Under Voltage Control status
ON: LDC outputs low voltage (12.8V)
OFF: LDC outputs normally
LDC power Derating status
ON: Power is limited by LDC internal failures Temperature sensor failure OR Temperature > 78℃ Input voltage is 180~200V LDC output current is higher than 135A OR
OFF: LDC is OK
LDC output voltage
Normal range: 12.8~14.1V
LDC control may stop if output voltage is lower than 9.0V or higher than 18V V
LDC output current
Nominal value is 130A, Max current is 135A by over current protection function. A
LDC input voltage
Normal range: 200~310V
180~200V: output power is limited
V < 180V or V > 345V : LDC control may stop.
LDC temperature
Temp sensor failure: 127℃
T > 78℃: power limit, T > 105℃: LDC stops ℃

29. Monitor strategy descriptionBE
DTC (MCU/GCU)
To understand the meaning of DTC for MCU system.
Material:
Trainees textbook
Method:
Lecture
Lead over:
DTC (MCU / GCU)
System
DTC
Monitor strategy description
Threshold
Time
MIL
MCU
power module (IGBT)
P0A78
Too high current in IGBT switch
Current > 2,800A
7 times within 10s.
2DC
Power supply voltage of power module is too low
Voltage < 9V
immediately
Open circuit in IGBT
Half-sine wave
0.5s
Power cable
P1C64
Motor power cable open circuit
Cable current < 10A
20ms
Motor Current sensor
P0A51
Short or open circuit in A/C current sensor
Output>4.65V or <0.35V
5ms
P0A52
Rationality check
T.B.D
Inverter Temp. sensor
P0AF0
Open circuit or short to high voltage
V > 4.85, T > 30℃
100ms
P0AEE
P0AEF
Short to ground
V < 0.5
Motor Temp. sensor
P0A2D
V > 4.83 1s
P0A2C
V < 0.15
P0A2B
Slide page only

30. Motor rotor position sensorBE
DTC (MCU/GCU)
To understand the meaning of DTC for MCU system.
Material:
Trainees textbook
Method:
Lecture
Lead over:
DTC (MCU / GCU)
Component
DTC
Malfunction criteria
Threshold
Time
MIL
Motor rotor position sensor
P0A3F
Open or short circuit
V > 4.25 or < 0.75
660ms
2DC
P0A40
Rationality check
T.B.D
P0C17
Rotor position sensor calibration
Calibration flag
immediately -
Motor Over-heat
P0A3C
Inverter overheat check
T > 102℃ 1s
P0A2F
Motor overheat check
T > 185℃
10s
Motor Over current
P0A78
Over current checking
Current > 450A
3 times within 10s
HSG power module
P0A7A
Too high current in IGBT switch
Current > 2,800A
7 times within 10s.
Power supply voltage of power module is too low
Voltage < 9V
Open circuit in IGBT
Half-sine wave
0.5s
HSG power cable
P1C6A
HSG power cable open circuit
Cable current < 10A
20ms
Slide page only

31. HSG rotor position sensorBE
DTC (MCU/GCU)
To understand the meaning of DTC for MCU system.
Material:
Trainees textbook
Method:
Lecture
Lead over:
DTC (MCU / GCU)
Component
DTC
Malfunction criteria
Threshold
Time
MIL
HSG Current sensor
P0A59
Short or open circuit in A/C current sensor
Output > 4.65V or < 0.35V
5ms
2DC
P0A5A
Rationality check
T.B.D
GCU Temp. sensor
P0BCF
Open circuit or short to high voltage
V > 4.85
100ms
P0BCD
P0BCE
Short to ground
V < 0.5
HSG Temp. sensor
P0A39
V > 4.83, T > 30℃ 1s
P0A38
V < 0.15
P0A37
HSG rotor position sensor
P0A4B
Open or short circuit
V > 4.25 or < 0.75
660ms
P0A4C
P1C76
Rotor position sensor calibration
Calibration flag
immediately -
Slide page only

32. High voltage interlockBE
DTC (MCU/GCU)
To understand the meaning of DTC for MCU system.
Material:
Trainees textbook
Method:
Lecture
Lead over:
DTC (MCU / GCU)
Component
DTC
Malfunction criteria
Threshold
Time
MIL
HSG Over-heat
P0A3E
Inverter overheat check
T > 102℃ 1s
2DC
P0A3B
HSG overheat check
T > 185℃
10s
HSG Over current
P0A7A
Over current checking
Current > 250A
3 times within 10s
CAN
U0001
C-CAN bus off check
T > 1s -
U1001
H-CAN bus off check
U0293
HCU message missing (C-CAN)
T > 0.5s
U1004
HCU message missing (H-CAN)
U0111
BMS message missing (C-CAN)
T > 2s
U1006
BMS message missing (H-CAN)
U1116
EWP message missing (C-CAN)
EWP
P0C73
EWP performance
EWP status = SET
Immediately
High voltage interlock
P0A0D
Open connector of high voltage cable
Interlock V > 3.5
0.3s
CPU
P0A1B
CPU communication failure
Goes to ‘disable’ mode
immediately
Slide page only

33. DTC (LDC) BE DTC (LDC) Component DTC Malfunction criteria
LDC Voltage Control Error (P0A94)
This is detected if the difference between the LDC internal command value (Vt) and the actual DC output voltage value (Vo) is more than 1V.
Output Terminal Short Circuit or Input Terminal Disconnection (P0A94)
This is detected if the LDC output terminal is short circuited or the input terminal is disconnected.
In the case of the input terminal, the following conditions will trigger the error code.
MCU input voltage exceeds 200V - The BMS main relay is ON and the BMS is operating normally. - LDC input voltage is below 100V
Temperature Sensor Disconnection (P0C3A)
This is detected when the sensor detected voltage is above 4.7V.
Temperature Sensor Ground Disconnection (P0C3B)
This is detected when the sensor detected voltage is below 0.3V.
Overheating Malfunction (P1A88)
This is detected when the temperature of the power module in the LDC is over 105℃.
Current Sensor Malfunction (P1A89)
This is detected when the sensor detected voltage is above 1.5V.
To understand the meaning of DTC for LDC system.
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
DTC (LDC)
Component
DTC
Malfunction criteria
Release condition
Failsafe
MIL
Voltage control
P0A94
Vt – Vo > 1V for 10sec (Abnormal LDC voltage control)
IG Off & On
LDC operation stops -
Output terminal
LDC output terminal is shorted
Input terminal
LDC input terminal open circuit
Temp. sensor
P0C3A
Sensing voltage is high than 4.7V
LDC output is limited
P0C3B
Sensing voltage is lower than 0.3V
Over heat
P1A88
Temperature in diode is higher than 105℃
T < 73℃
Current sensor
P1A89
Sensing voltage < 1.5V
To be determined
CAN
U0001
CAN Bus off for 1sec
As soon as the communication restarts.
T.B.D
U0293
HCU CAN signal missing for 2sec
U0111
BMS CAN signal missing for 2sec
U0110
MCU CAN signal missing for 2sec

34. Actuation test - MCU BE MCU / GCU (Inverter) service data
The definition of the GCU-related service data supported by the diagnosis tool and the diagnosis procedure are detailed as follows:
Main Relay Cutoff Request Flag by the MCU
It shows the cutoff request of high voltage main relay. If the status is ON, then the request is made. In this status, a failure in which the high voltage relay needs to be cutoff from the MCU has occurred and the motor cannot be operated.
Capacitor Voltage
It displays the input DC-link capacitor voltage of the inverter or the MCU/GCU. If the main relay is OFF during initial engine start, a value closest to zero (0) is displayed. If the main relay is ON and there is no input or output of motor power, then the value equal to the battery voltage value will be indicated.
Motor Controllable Flag
The motor controllable flag displays whether or not the motor is in operable state. The status is maintained as OFF if ignition key start does not turn on, the auxiliary battery (12V) voltage is low, high voltage is not connected, or MCU failure occurs.
MCU Ready Flag
The MCU ready flag indicates that the MCU is ready for operation. If the MCU is ready for operation after the ignition is turned on, then ON is displayed and the MCU communicates signals with other control units. If OFF is displayed, then EV Mode is not available. But the engine can still be started via GCU. (However, the engine can only be started via GCU if high voltage is connected and ‘Ready’ and ‘Controllable flag’ of the HSG control unit (GCU) are on.
MCU Service Lamp ON Request Flag
The MCU Service Lamp ON Request Flag is the request to turn on the lamp to alert the driver of MCU or motor failure. In general, EV mode is not available when the service lamp is on, but if the ON is caused by disconnection / short circuit of the temperature sensor, then limited EV Mode driving is possible.
MCU MIL ON Request Flag
If MCU or motor failure that can affect the emission performance occurs, then the MIL lamp ON is requested in accordance with OBD regulation. If the same failure occurs consecutively for 2DC (Driving Cycle), then the indicator lamp turns on. If the same failure does not occur for 3DC, then the MIL lamp ON request is cancelled.
Motor Actuation Test Flag
The motor actuation test flag is to prevent other master control unit activates the motor when forced operation of the motor is engaged. If the motor actuation (torque control, speed control) and supplementary function (resolver offset calibration) is engaged, the actuation test flag is turned on to alert the other control units.
MCU Warning Flag
The MCU warning flag is an alert signal that indicates MCU warning and shows that power limited drive is engaged. If the indication is ON, then ‘power limited EV Mode’ is possible.
MCU Fault Flag
If a failure in the MCU or the motor occurs, and normal operation is not possible, the fault flag indicates ON and alerts other control units.
MCU Temperature
It displays the detected temperature value of the IGBT base plate of the MCU. The rate of temperature increase becomes greater as the MCU output increases. If the MCU temperature reaches above 90℃, power-output-limited driving is engaged, and if the temperature exceeds 95℃, then the output torque becomes zero.
To understand the meaning of service data in the scanner of MCU (inverter) / GCU system
Material:
Trainees textbook
Scanner
Training vehicle
Method:
Lecture
Lead over:
Actuation test - MCU