1. Electronic Control Unit (ECU)
Topics covered in this presentation:
ECU Operation
ECU Components
In Car Position

2. Electronic Control Unit
Also Known as Electronic Control Module (ECM) and Powertrain Control Module (PCM).
Vehicle management is by ECU, which acts as a computer.
Three stages of operation: INPUT-PROCESS-OUTPUT.
Next >

3. Question 1 Which of these does NOT provide an input to an ECU?
A) Display
B) Magnetic pickup
C) Variable resistor
Correct Answer = A
D) Switch

4. ECU Operation Inputs come from sensors and switches.
CPU processes input readings and compares with ideal data, stored in memory.
Outputs to actuators make adjustments that improve:
Efficiency.
Power.
Controllability.
Safety.
Next >

5. Simplified ECU Control System
Typical ECU and controls: Q
ECU E N D R M L K C A G F O H P J I B
A. Engine temp sensor
G. Canister purge valve
M. Fuel pressure regulator
B. Oxygen sensor
H. Canister air valve
N. Camshaft sensor
C. Knock sensor
I. Charcoal canister
O. Crankshaft sensor
D. Mass airflow sensor
J. TPS
P. Diagnosis lamp
E. Vacuum controller
K. Air temp sensor
Q. Ignition coil
F. EGR valve
L. Idle actuator
R. Injector
Next >

6. Question 2 Which of these is NOT connected to an ECU output?
A) Vacuum controller
B) Idle actuator
C) Fuel pressure regulator
D) Engine temperature sensor

7. ECU Internal Circuits Input circuit conditions signals.
Processing circuit compares information.
Output circuit switches actuators.
Power supply provides stable voltages to circuits.
Next >

8. Question 3
Why is it important to have stable voltages supplied to sensors?
A) To avoid damaging the sensors
B) To prevent them acting as switches
C) To prevent them providing false readings
Correct Answer = C
D) To prevent them becoming actuators

9. Processing Circuit Components - The CPU
CPU performs decisions and calculations.
Contains hundreds of logic gates, which operate with binary numbers.
Next >

10. Question 4
Which of the following is a function of the central processing unit (CPU)?
A) Measuring voltages
B) Making decisions
C) Setting the clock frequency
Correct Answer = B
D) Manufacturing logic gates

11. Processing Circuit Components - Memory
Read Only Memory (ROM)
Contains program to control ECU.
Processing components
Program is vehicle generic.
Information cannot be changed.
Random Access Memory (RAM)
Temporary memory.
Used by CPU to store and retrieve data.
Data lost when power removed.
Next >

12. Processing Circuit Components - Memory
Programmable Read Only Memory (PROM /EPROM)
Program that is vehicle specific.
Processing components
Can be updated.
Read only.
Keep Alive Memory (KAM)
Stores adaptive strategies.
Supplies default data if fault occurs.
Data is not lost if vehicle battery disconnected (has own internal battery).
Next >

13. Question 5
Which of the following types of memory will lose data when the power is switched off?
A) PROM
B) KAM
C) ROM
Correct Answer = D
D) RAM

14. Question 6
Which type of memory contains generic information to control the ECU?
A) ROM
B) RAM
C) PROM
Correct Answer = A
D) KAM

15. ECU Housing and Location
Hard metal or plastic case, with a connector(s) for multiple wires.
Located away from moisture, heat and vibration.
Housing
Connectors and wires
Next >

16. Question 7
Moisture is a hazard to ECUs because it can coat insulators and allow them to conduct electricity. Is this true or false?
Answer True or False.
Correct Answer = T

17. Different Types of ECU Sometimes split into specific areas. Main ECU
Instrument cluster
unit
Anti-lock
brake unit
Main ECU
Suspension
unit
Next >

18. Static Electricity Precautions
People can become charged with static electricity.
Charge stays until conductive material touched.
Static electricity damages internal components of electronic devices (ECU).
Touch suitable ground point to discharge.
Rubber gloves may prevent static electricity build up and transfer.
Next >

19. Question 8
Static electricity transfer can be prevented by wearing rubber gloves. Is this true or false?
Answer True or False.
Correct Answer = T

20. Summary You should be aware of: ECU Operation ECU Components
In Car Position
End >