Thomas Built Buses TBB 6002 Saf-T-Liner HDX Chassis Electrical

Thomas Built Buses TBB 6002 Saf-T-Liner HDX Chassis Electrical Student Guide

Saf-T-Liner HDX Chassis Electrical
Course Objectives locate primary system components locate harness and wiring routing read and understand Thomas drawings understand J1587 and J1939 utilize ICU for diagnostics follow troubleshooting procedure Objectives This course will focus on the vehicle’s electrical system. The chassis is the host component for customer selected options designed to meet their market needs. The system is a combination of systems; engine, transmission, ABS braking, Cooling, OEM options This course will focus on the Thomas electrical options and consumers and their interface with the other systems. TBB6002 Page

Course Content Primary System Components Battery, Ignition, Ground Wiring and Harnesses Understanding Thomas Drawings J1587 and J1939 Retrieving fault codes Evaluation Content Each of these sections contain the information required to locate system components, understand their function, and relationship to other electronic systems There are many possible electrical options offered so not all combinations will be covered but familiarity with the foundation components should make the troubleshooting and repair of different combinations of options easier. TBB6002 Page

Section 1 Primary System Components Saf-T-Liner HDX Chassis Electrical
The HDX is a Type D product manufactured by Thomas Built Buses in High Point, NC The rear engine configuration has changed in its appearance and electrical systems over the years. For many years Thomas built two basic pusher configurations The MVP-ER which had a belt driven street side cooling system and a small curb side mounted rear electrical box The ER-Transit had a curb side hydraulic cooling system and large street side mounted rear electrical box Both models had roped-in front windshields In 2000 the pusher under went an update and was called the “New Look” with hydraulic cooling system and bonded front windshield. The HD model was introduced in 2002 with a 3 piece panel front compartment access. This course will cover the HDX that is being currently produced 2007 prior to the 07 engine changes. TBB6002 Page

Primary Components Locations Front Interior Compartment Transmission Control Center Engine Compartment Primary System Component Locations Obviously with a rear mounted engine-transmission the system’s components are located in the front and rear of the bus with wiring to connect the systems. The front interior compartment is a locked cabinet space in the right side of the dash. The transmission control center is under the bus attached to the left frame rail The engine compartment is the area enclosing the cradle mounted engine and transmission. TBB6002 Page 1-2

Primary System Components Front Interior Compartment Primary System Components Front Interior Compartment One of the improvements from earlier pusher type models is the HDX electrical system has components consistently in 3 locations The front compartment contains components that control OEM basic type consumers, as well as engine, abs and popular customer options like auto tank drains and driveline retarder The HDX employs a Printed Circuit Board like the Body as its primary control and distribution component for managing electrical circuits and consumer behavior TBB6002 Page 1-3

Primary System Components Front Interior Compartment ABS ECU Primary System Components Front Interior Compartment The chassis PCB is identified as PCB4 The drawings also use the –C or P5-B4=P5-C, this is obviously a Body versus Chassis engineering sort of thing Turn in your Student Drawing Packet to Page 9 drawing Please note the LED diagnostic lights are on B4 but not listed on the on-board label Obviously the LED assignments can be found in other information to be covered PCB4 is not the same internally as PCB1 or B2 on the Body Also in the compartment are the WABCO, or Bendix in the past, ABS ECM and the Signal Stat module The are all standard locations for all HDX buses for these components. PCB#4 Signal Stat Printed Circuit Board 4, ABS Control Module Signal Stat Module TBB6002 Page 1-4

Primary System Components Front Interior Compartment Primary System Components The front compartment contains the DRL (daytime running light) module, a 9 Pin Deutsch type data link connector for computer diagnostics, and up to three vehicle electrical centers (VEC) for additional options. These VECs are called front since there is a rear VEC as well in the engine compartment. Front VEC Centers 9 pin Data Link Daytime Running Light Module Option VEC Centers, Daytime Running Light Module, 9 pin Data Link Connector TBB6002 Page 1-5

Primary System Components Front Interior Compartment Primary System Components Front compartment If the bus is powered by a Mercedes engine then the VCU-vehicle control unit is located inside the compartment Mercedes has a PLD mounted on the engine for control of system operation and the VCU for parameter , vehicle interface and diagnostic interface. These two computers are joined by data circuits Mercedes Engine VCU TBB6002 Page 1-6

Primary System Components Front VEC Centers Primary System Components Front VEC centers These centers are sources of battery powers for customers options not “standard” The power is delivered to an internal buss bar in each center and parrallel circuit designed circuits used. The pictured labels are standard for each center though not all labeled fuses and relays will be on a specific bus So you can have one, two or three of these centers on any HDX These centers are identified as P190, P220 and P221 in your drawings These centers could be used to power an aftermarket add-on since there are normally unused connectios identified as P190, P220, P221 in drawings provides additional connections and control for various options TBB6002 Page 1-7

Primary System Components Transmission Control Center Primary System Components Transmission Control Centers This box contains the transmission TCU module and the VIM, vehicle interface module. It is mounted at the front axle to the inside of the left frame rail On older pushers the TCU was in the front interior compartment It is essential that the cover always remain in place. The cover is secured at the bottom so it can be easily removed for service located on left frame rail at front axle contains transmission TCU and VIM See Drawing# TBB6002 Page 1-8

Transmission Control Center Vehicle Interface Module - VIM Primary System Components Transmission Control Centers The VIM-vehicle interface module is a signal distribution center Buses can be equipped with many options with behavior that requires the confirmation of specific signals before operation can proceed Example, driver should not be allowed to start the engine unless, the bus is in neutral The VIM is a location used to connect the wires that communicate signals. Since the transmission supplies or is most concerned with this information the VIM is mounted close to the TCU The label for the VIM is on the backside of the Bussman cover for the VIM service brake active signal to TCU neutral start neutral sense- fast idle, lift operation reverse- signal from TCU for back-up alarm retarder active – signal for brake lights TBB6002 Page 1-9

Primary System Components Rear Box Primary System Components Engine Compartment One of the more noticeable changes to the engine compartment of the HDX from earlier models is the rear electrical box This small rear box is mounted to the top center of the engine compartment The rear box is the control component for engine compartment systems supplying battery power and ignition to rear gauges, engine and cooling system module. The switches mounted on the rear box allow for rear starting and control of battery power to the body and chassis so ignition travels from the key switch to the rear box and back to PCB4 standard size rear ignition, start TBB6002 Page 1-10

Primary System Components Rear Box See drawing# VEC 9 pin Data Link Primary System Components Engine Compartment See drawing On the outside of the rear is the VEC, another 9 pin Deutsch data link connector and the 100 amp contactor Not pictured is the optional low coolant module mounted to the left side beside the VEC-this module will be standard on buses with 07 engines 100 amp Contactor TBB6002 Page 1-11

Primary System Components VEC-Vehicle Electrical Center Primary System Components Engine Compartment The VEC is the battery supply location to the engine ecu, fan controller and relay battery power for air dryer and restart relays The VEC supplies ignition to the engine ecu and restart relay Battery power and ground for the VEC are located at the black connection on the VEC. rear ignition relay fan controller relay air dryer relay engine ignition power rear start relay power and ground to engine-mounted ecu TBB6002 Page 1-12

Section 2 Battery , Ignition and Ground
Saf-T-Liner HDX Chassis Electrical Section 2 Battery , Ignition and Ground Battery, Ignition and Ground The HDX product was the first Thomas product to employ some new system components for these circuits This section is designed to confirm the operation of location of these circuits TBB6002 Page

Battery, Ignition and Ground Battery Switches on Rear Box signal to Breaker Solid State Power Switch controls battery to Body and Chassis Battery, Ignition and Ground Battery Power Although not pictured the battery box is the starting point for this circuit Previous models had manual type 150 amp battery power breakers mounted in the engine compartment for the Body and Chassis. The HDX uses a solid state power switch as the battery power breaker The power switch contains FETs to sense the AMP load There is a cable connection for the 2awg cable from the battery and then two connections supplying the Body and Chassis See drawing for the installation of the power switch The power switch is control by the two switches on the rear box Please note the non-conductive pad between the rail and the power switch TBB6002 Page 2-2

Battery, Ignition and Ground Battery Battery, Ignition and Ground The 2 battery cables route up the right frame rail to the front bulkhead connections pictured The cables connect to the pass through studs at the bulkhead The chassis stud supplies PCB4 and the body stud supplies the cable connecting to PCB1 for the body system From Power Switch to Bulkhead studs then to PCB1 & 2 for Body and PCB4 for Chassis TBB6002 Page 2-3

Battery, Ignition and Ground Use Drawings# & to answer these questions Where is PCB4 grounded?_______________________ The intake heater has a _____amp breaker> The positive cable go from the battery to the _________. The negative cable on the alternator goes to the ______. The key switch on signal goes from the key switch to ___________ then to__________ then to ___________ What is the circuit number controlled by the engine compartment door?___________ What circuit number tells the start circuit the bus is in neutral?_________ List the fuse/s that could cause the ignition circuit to fail: ____________________________________________ Battery, Ignition and Ground Use drawing & to answer these questions Where is PCB4 grounded?_______________________ The intake heater has a _____amp breaker> The positive cable go from the battery to the _________. The negative cable on the alternator goes to the ______. The key switch on signal goes from the key switch to ___________ then to__________ then to ___________ What is the circuit number controlled by the engine compartment door?___________ What circuit number tells the start circuit the bus is in neutral?_________ List the fuse/s that could cause the ignition circuit to fail: ____________________________________________ TBB6002 Page 2-4

Section 3 Wiring and Harnesses Saf-T-Liner HDX Chassis Electrical Page
The MVP-ER, ER Transit and HD models since 2000 used pre-made harnesses These harnesses included the chassis, engine, transmission and abs The HDX combines these harnesses into two harnesses routed down the left frame rail This section will explain the new harness configurations and other wiring basics TBB6002 Page

Wiring Harnesses Types: Interior- dash Exterior- chassis inside left frame rail, front bumper Rear Box –inside the box See Drawing# This is a list by harness type (location) Note there are 17 interior harnesses, each bus only has 1. On older pusher models each system had its own harness like engine, ABS, Transmission These harnesses were combined into only 2 harnesses Only use the drawings that match your bus components like MBE,WABCO, Allison 3000 series Wiring See Drawing This chart explains the new harness combinations It is important that service resources be used that match the bus you have You could have a MBE, 3000, WABCO or a C7, 3000, WABCO Your drawing information will identify a circuit as being located in Internal harness-dash and front compartment Exterior harness-under the bus Rear box Basically you will have one internal harness, two external harnesses and a rear box The transmission and abs harnesses make one and the engine and chassis harnesses were combined into one harness What is the harness part number for an internal harness with MBE, 3000 Trans and WABCO abs?_____________ TBB6002 Page 3-2

Wiring Wiring An identifying feature of the HDX is the three piece front panel The 3-piece panel improved the service access and made the panel repair less expensive. The one piece panel can be changed over to the 3 piece 3 panel design allows easy access to front exterior harness and bulkhead connections TBB6002 Page 3-3

Wiring Bulk Head Wiring At the bulkhead are the primary harness connectors joining the internal and external harnesses Since they are a fixed male type connector they are “J” jacks/junctions The larger connector J76 has 102 pins and J75 has 60 pins The harness is connected to these J connectors with a 5/16 bolt J76 J75 Transition from Interior Harness to Exterior Harness Junction for battery and ground cables TBB6002 Page 3-4

Wiring Terminal Board Wiring Located inside behind PCB4 is Terminal Board 1-TB1 This 5 post board joins circuits for the ICU3 dash like J1587 and GND See drawing lower left Each post on the board is numbered so there are TB1-1, TB1-2, etc Older models had a TB2 inside of the rear box but TB2 has been eliminated on current production buses You may need to remove PCB4 for service access See drawing# attached to bulkhead behind PCB#4 used to combine common circuits; J1587, GND identified as TB1 in drawings older models had a TB#2 inside rear box TBB6002 Page 3-5

Wiring Wiring The HDX uses the SAE J2191 wiring standard so all wires are color coded and numbered every 4 inches Color implies function like pink is ignition, orange is abs color coded SAE J2191 standards numbered every 4 inches TBB6002 Page 3-6

Wiring Circuit Numbers 52#1104 Thomas # SAE Wiring The HDX chassis circuit numbers changed from the Thomas numbers used on earlier models The HDX uses the current Freightliner numbering system There are two circuit numbers on each wire The Freightliner number and the SAE number Since SAE numbers are assigned by function Use the Freightliner number when tracing a wire See drawing# start circuit Locate circuit 52#1104 Locate circuit 52B#1104 use the Thomas circuit number when tracing a wire The SAE number will be the same for circuits with similar functions TBB6002 Page 3-7

Circuit Numbers (SAE number has been omitted) Circuit number Description Color 1 Engine ECM bat gnd (in) W 6 Engine ECM bat power (in) R 19 Gauge power rear box PK 21 Headlamp high LTG 47 Fuel sender signal PK-W 48 Fuel level+ 52 Ignition Power Ignition 102 Marker power BR 116 Panel lamp ground 122 Roll back module power BL 173 Man trans clutch sw grnd(out) LTBL-W 196 Fuel water/separator power DKG-W 200 Remote throttle sig analog PRP 250 Ecm Ground(out) GY 278 Right control switch supply PRP-W 279 Left control switch supply 289 Transmission neutral signal 294 Air tank drain R/R-W 305 Ignition switch power Ignition access supply 306 Ignition run signal Wiring Circuit numbers This is a list of Freightliner circuit numbers The SAE number is not listed This is meant to be a reference TBB6002 Page 3-8

Circuit Numbers 307 Headlamp power GY LTG 309 Park brake input R-W 320 Windshield wiper PRP-W 335 A/C signal LTBL 342 Ammeter signal PK 385 DRL power 392 Adj pedal signal 393 Adj pedal return 431 Preheater power DKG 443 Door signal T-W 446 Snow chain 108A Stepwell light 1139Y Water in fuel light gnd 122A Roll back module signal BL 136B Neutral signal 14BS Gauge power R 14E Chassis power LED 18G Low air pressure SW jumper W 200J PTO set speed B signal PRP 222F Hdlmp dim sig flash to pass 222L Hdlmp dim sig lh turn 233B Opt indicator lamp RW 23C Backup lights BR 262B Retarder signal (in) TBB6002 Page 3-9

Circuit Numbers 262G Retarder in use R-W 262K Brake switch signal 278A Right wiper motor park supply PRP-W 278B Right wiper motor low supply 278C Right wiper motor high supply 279A Left wiper motor park supply 279B Left wiper motor low supply 279C Left wiper motor high supply 294A Air tank drain 29A Lamp power supply BR 29D Lamp ground GY/BR 30G Transmission Temp- LTBL-W 315A Wiper module park DKBL 315B Wiper module low 315C Wiper module high 342A Ammeter common W 376A Battery power R 376C Ignition power O 376II ABS relay active signal 376J ABS ECU serv brake signal 376LI ABS lamp 376R Retarder disable signal 377LF+ Left Front wheel speed signal 377LFO Left front modulator exhaust 377LR- Left rear wheel speed return TBB6002 Page 3-10

Circuit Numbers 377LR+ Left rear wheel speed signal BR 377RF- Right front wheel speed return O 377RF+ Right front wheel speed signal 377RR- Right rear wheel speed return 377RR+ Right rear wheel speed signal 378LF- Left front modulator common W 378LFI Left front modulator hold 378LR- Left rear modulator common 378LRI Left rear modulator hold 378RF- Right front modulator common 378RFI Right front modulator hold 378RFO Right front modulator exhaust 378RR- Right rear modulator common 378RRI Right rear modulator hold 378RRO Right rear modulator exhaust 38L Left turn signal Y 38R Right turn signal DKG 392A Adj pedal return R-W 393A Adj pedal signal 406D Crossing arm PRP-W 406E Child alarm 431C Intake Grid Heater Lamp 431H Grid heater ground(out) 439+ CAN+ (out) GY 439A Ignition power TBB6002 Page 3-11

Circuit Numbers 439D- CAN- (in) GY 439S- V speed signal (return) 439S+ V speed signal (in) 439U Ignition ground(out) PRP 439V Fast idle indicator lamp sig 439W- H2O in fuel sensor return 439W+ H2O in fuel sensor signal 440A Dash check eng lamp 440B Dash park brake lamp Service brake switch 440E Cruise set signal 440F 440G Serv brake SW W 440OT TPS sensor ground 440P- TPS sensor signal- 440P+ TPS sensor signal+ 440S Dash buzzer ground Stop eng dash lamp 440V1 Idle validation(NC) signal 440V2 Idle validation(NO) signal 443G Door return DKBL 461A Reverse signal BL 47G Fuel sender ground 48G Fuel level- PK-W 52B Ignition PK TBB6002 Page 3-12

Circuit Numbers 52C Start signal PK 58E Coolant pump LTBL 60A Right turn signal Y 61A Left turn signal DKG 6A Battery power R 6B 6C 6D 6E 6F 71AA Ignition power 71B Key SW starter interlock 98A Heater fan low 98AD Defrost fan low 98B Heater fan medium 98H Heater fan high 98HD Defrost fan high 98PD BAT C840 Emission signal GY C844 Emission signal return C857 Starter lockout Engine running signal C998 Emission return E002 BK TBB6002 Page 3-13

Circuit Numbers E003 Battery power sensor BK E008 Retarder enable W E009 Ground E014 Reverse signal E033 Dimmer power PK E107 Solenoid G return E110 Solenoid F return E1106 Key SW aux range inhibit E1107 Second shift schedule E1109 Exhaut brake signal E1110 Retarder disable signal E1123 Range inhibit E1125 Trans Ind Lamp Range inhibit signal E1126 Trans TCU speed signal T E1128 Brake return signal E119 Exhaust brake signal E120 Solenoid A return E121 Solenoid B,E supply E1212 Transmission temp lamp E123 Power for neutral signal E128 Solenoid B return E130 Solenoid C,G supply E131 Solenoid D return E139 Output speed sensor TBB6002 Page 3-14

Circuit Numbers E141 Engine speed sensor T E144 Sensor ground BK E147 Sump temp signal E162 C3 pressure signal E165 Oil level signal E169 Exhaust brake signal E170 Shift selector data bit 1 E171 Shift selector data bit 2 E172 Shift selector data bit 4 E173 Shift selector data bit 8 E174 Shift selector parity bit E180 Shift selector display E195 Transm Idle signal GND Ground W GNDE Electronics ground GNDH Heater ground J1587- O J1587+ DKG J1587S J1587 shield shield J1939- J1939+ Y J1939S J1939 shield N23 Idle signal GY N31 Wait to start light gnd N98A ECM power N98B N98C TBB6002 Page 3-15

Wiring Maintenance Dos: inspect wires repair properly protect Don’ts: damage when testing make poor repairs leave loose Wiring Reliability, durability are yes a part of design but we as techs can choose to Contribute to longevity or condemn our system to an early retirement Problems with a wire path is what we have to find and fix most of the time So -when you are looking for a problem or gaining access to a circuit to test, Be careful don’t pull other wires apart, -when you move/remove a harness held with clamps or tie wraps, put them back securely -a soldered repair is always better than a scotch lock; repair properly -probing a wire connector or terminal can damage that wire and others around it so use spoons or properly sized tools; don’t cut the insulation which creates a spot for corrosion Return to manufacture’s standard or improve it TBB6002 Page 3-16

Wiring Each harness connector is labeled with a “Plug Number” Wiring Harnesses On the HDX chassis the plugs on the pre-made harnesses are labeled with the harness assembly number and the “P” plug number This plug number ties the plug on the chassis to the plug shown on a drawing Don’t remove the labels since they are a useful aid The plug number will be referenced in the drawings Don’t remove the white labels TBB6002 Page 3-17

Harness Plug Location Number Description Location B58 Butt splice at Back-up Alarm Engine Compartment B59 BS14 Butt splice at luggage compartment light Luggage Compartment BS20 Butt splice at Booster Pump BS22 Butt splice at Engine Compartment Door Kill Switch P100 ABS ECM Interior Chassis Elec Center P102 Right Front ABS Modulator Front Axle P103 Right Front ABS Sensor P104 Left Front ABS Modulator P105 Left Front ABS Sensor P109 Adjustable foot pedal switch Dash P111 Throttle Postion Sensor Pedal P115 Shift Selector P12 Right Turn P120 Adjustable foot pedal motor Cab at pedal P122 9 pin Deutch connector P13 Left Turn P167 Single pin connector at fan controller P168 Two pin connector at fan controller P17 Engine ECM P183 Air Tank Pressure Sender Air Tank P184 Harness Plug Locations This is a list of harness plug numbers It is meant as a student reference Where is P246?_______ TBB6002 Page 3-18

Harness Plug Locations P190 Fuse center below PCB#4 Interior Chassis Elec Center P192 Heater at floor on left side of heater Cab P196 Diode Block mounted to inside firewall P207 Right Front Turn Signal Front External Bulkhead P209 Left Front Turn Light P211 Left Wiper Motor P217 Wiper Module P218 Steering Column P221 P229 Rear Ignition Switch Rear Box Engine Compartment P230 Engine Start Switch Rear Box P231 Engine Compartment Light Switch P232 Chassis Power Switch Rear Box P233 Body Power Switch Rear Box P246 Mercedes VCU/brown P247 Mercedes VCU/gray P248 Mercedes VCU/purple P276 Luggage Compartment Switch Cab Switch Panel P287 J1939 Data Link connection to Transm TCU Forward of Front Axle P288 Air Dryer P43 Daytime Running Light Module P46 P50 Key Switch Dash P53 Cruise On/Off Switch P54 Cruise Set/Resume Switch TBB6002 Page 3-19

Harness Plug Locations P60 Dimmer Switch Steering Column P64 Pink connector to ICU Dash P65 P74 Stepwell light Stepwell P75 62 pin Bulkhead Connector Front External Bulkhead P76 102 pin chassis bulkhead connector P78 VEC/Black outside rear box Engine Compartment P79 VEC/Gray outside rear box P8 Right Head Light P80 VEC/Blue outside rear box P81 VEC/Green outside rear box P83 Rear electrical box P85 VEC 2 pin outside rear box P9 Left Head Light P93 J1939 terminating resistor Interior Chassis Elec Center P96 Fuel/Water Separator Sensor P99 ABS ECM T12 Single ring terminal at Battery+ Battery Box T13 Single ring terminal at Battery- T14 T16 Single ring terminal at alternator Alternator T18 Single spade terminal at washer motor T19 TB2-1 Terminal Board 2 inside Rear Box TB2-2 TB2-3 TBB6002 Page 3-20

Section 4 Understanding Thomas Drawings
Saf-T-Liner HDX Chassis Electrical Section 4 Understanding Thomas Drawings Understanding Thomas Drawings In this section the student will learn the organization, symbols and types of Thomas drawings by using the drawings to answer questions Please review each question with the class after the students have had some time to answer independently TBB6002 Page

Thomas Body PCB Electrical
Understanding Thomas Drawings Types Charts- a visual graph displaying routing and/or options information used as reference Installation- a visual representation of either the component installation like harness routing or the installed component Assembly- a visual representation of every piece used to make the assembly includes dimensions and part numbers assembly drawing numbers are the part number for the assembly Schematic- a visual representation of the flow of electricity through a specific path including all components used primarily for diagnostic purposes Understanding Thomas Drawings Point out examples in the drawing packet of each type in the packet installation , Chart Assembly Schematic Drawing are body number, vin number specific Drawings can be accessed via mytbb.thomasbusonline.com Page 4-2

Understanding Thomas Drawings Installation Drawing Answer the following questions using Drawing#130479 On a MBE engine when is the fan turned on?________ How long does it take for the fan to Ramp UP?_______ Where is the battery supply connected to the module? _____________________________________ At what temperature is the alarm activated?________ Answer the following questions using Drawing# What is the part number of the VIM?________________ How many fasteners are required to install the TCU?___ TBB6002 Page 4-3

Understanding Thomas Drawings Assembly Drawings Use Drawing# to answer these questions What is the distance from the Bulkhead to the Body Chassis Interface?_________ Where would I find CHAS_H_PCB_P22-C?__________ Describe a plan to locate splice S7 on the bus?______ ____________________________________________ How many cavity positions are in P76?______ Circuit 200#1413 starts at plug______ pin no______ and goes to plug______ pin no______. What is the function of wire 379A ?_____________ What is the vendor’s part number for circuit 37 in P220? _________ TBB6002 Page 4-4

Understanding Thomas Drawings Locate Drawing# Common Systems Where would I find P11-C? _____________________ What is the plug number for the DRL module?______ What color is circuit 37#1313?___________ What is the pin location for circuit 279C#2102 at the wiper module?_____________ The bold vertical dotted line indicates________________ Locate J76, the connector is drawn different at the top than at the bottom; why?_________________________ What major system component is located at grid location D3?_______________________ Locate circuit 439A#1512 at grid C5; where would I find the other end of this wire?____________________ TBB6002 Page 4-5

Understanding Thomas Drawings Answer the following questions using Drawings# and Relay#_____ on PCB4 supplies B4 buss bar with ignition power. PCB4 has ______ 30amp buss bars. LED#17 on PCB4 is ________ and tells the bus the ________________ is in use. The decal found on the back of the front interior compartment will tell me what each LED light indicates. Yes or No What is the horn fuse number?________ _______amps Relay K-1 is used for _____________________. Where can I located the wire that signals the body that the key switch is on?_________________________________ PCB4 supplies the ABS _____________________________ TBB6002 Page 4-6

Understanding Thomas Drawings Locate Drawing# Common Systems Complaint: left headlight does not come Draw a straight line schematic for this circuit What could cause this complaint?___________________ Where should I begin testing?______________________ TBB6002 Page 4-7

Section 5 J1587 & J1939 Saf-T-Liner HDX Chassis Electrical Page
J1587 and J1939 Over the years as more and more electronic systems are employed to improve and speed up response and operation while offering more control and customer choices, the use of digital systems has accelerated. Using digital offers speed and component reductions, instead of having a sensor for each system all systems can share sensor information All buses since 1999 use digital data exchange at least between the engine ECM and the transmission TCU TBB6002 Page

J1587 ICU3 TCU VCU ECU ABS J1587 There are two digital exchange networks on the HDX Exchange means communication, electricity broadcast by system computers share inform The J1587 network is two 16 gauge wires twisted one time per inch Unless a computer is connected to the wires it cannot communicate The speed of J1587 is 9,600 bits per second so it is too slow for operational control The ICU3 dash receives is data from the engine ecm on J1587 The ICU and ECM connect at TB1. If this connection is lost none of the gauges would work The system computers use J1587 to transmit active fault codes and turn on driver dash mounted indicator lights Used for Communicating outputs – dash indicators, active fault code, ICU BAUD rate 9,600 bits per second orange and green wires twisted once per inch Each of the system modules uses these wires The ICU3 gets its gauge, voltage and odometer info via 1587 from engine If J1587 is open what behavior will the driver report? _________________________________________ TBB6002 Page 5-2

J1939 Hydraulic Control module TCU VCU ECU ABS J1939 These high speed data wires can be used for operational control The system computers can exchange digital data at 256,000 bits per second So data is sent down the wires in varying voltages and at varying frequencies. Since it is digital and since the information that is shared is critical the connected computers will not operate properly if they can not send and receive information. The engine will de-rate if it does not get vehicle speed from the TCU The shift inhibit light will come on if the TCU does not know Engine RPM Instead of having its own coolant and intake air sensors the hydraulic fan control module gets this data via J1939 from the engine. Without this data the controller defaults to system protection so the fan turns at max rpm Used for Communicating outputs – digital signals to other systems BAUD rate 256,000 bits per second yellow and green wires twisted once per inch bi-directional path What does the Engine tell the Transmission? _____________________________________ What does the Transmission tell the Engine? Does the Hydraulic Fan Control Module use J1939 for outputs or inputs?_______________ TBB6002 Page 5-3

J1939 120 ohm Terminating Resistors-TR Required to maintain consistent environment for data Locate at front and rear of harness (bus) J1939 The function of J1939 dictates certain design and construction standards be applied and maintained Since a message or data is electricity anything that can alter electricity can change the message The environment of the data link must be constant and consistent A 8 volt message sent by one computer can not change to 7.5 volts so the wires have a consistent resistance value Next in order to eliminate any repetitive messaging resistors are located at each end of the datalink harness On the HDX these terminating resistors are located at the rear box and inside the front interior compartment. These resistors are 120 ohms each TBB6002 Page 5-4

J1939 Construction and Repair J1939 Pictured is an example of a connection in the datalink harness These Deutsch pin type connectors use gold plated round pins for maximum conductivity and connectivity. If these pins are damaged they can be repaired with special crimpers If the yellow or green wire is damaged it can be repaired a maximum of two times per color. The repair must be a soldered joint with heat shrink Since heat can change resistance in any wire it is important to keep these wires away from hot components. round Deutsch pins special crimper required gold plated pins replace bad connectors replace harness by section or solder twice per color TBB6002 Page 5-5

J1939 Hands-on Activity If J1939 is open between the engine and transmission, what behavior would the driver report? _______________________________________ What happens if the Hydraulic Fan module does not receive temperature data? ______________________________________ Use handout to conduct testing of J1939 J1939 Hands-on activity Pass out hand out 54-15 and turn to page 5 Review the testing of these circuits and the values on the table on page 5 Have the students test J1939 Remove a terminating resistor and retest TBB6002 Page 5-6

J1587 & J1939 Hydraulic Fan Control Module J1939 This page and the next come from the service manual for Parker’s hydraulic control module It explains the diagnostic usage of the LED lights on the module Disconnect the engine’s coolant temperature sensor and use the LED lights to troubleshoot TBB6002 Page 5-7

J1587 & J1939 Hydraulic Fan Control Module TBB6002 Page 5-8

Section 6 Retrieving Fault Codes Saf-T-Liner HDX Chassis Electrical
Retrieving Active Fault Codes This section will explain the role of the dash in displaying fault codes and students should use the dash to retrieve an active fault TBB6002 Page

Retrieving Active Fault Codes Retrieving Active Fault Codes As explained previously the dash receives its data via J1587 The ICU3 dash is a microprocessor translating the data into visual gauge and indicator lights for driver information When an active fault code is transmitted by a system’s ecu the ICU dash displays that information The ICU dash is only a reader so it does not directly communicate with the system sending the fault The active fault code is displayed where the odometer and volts display would be seen ICU dash cluster is a micro-processor receives data via J1587 and displays any system module with an active fault will transmit code via J1587 code will be displayed in LED screen TBB6002 Page 6-2

Retrieving Active Fault Codes Retrieving an Active Fault Code The reset/mode button must be manipulated to retrieve the full code contents Before this retrieval can be done the park brake must be set and the ignition key be on. Active faults can not be cleared with this button Any active code will continue to be displayed until the problem is repaired Before Code Retrieval: locate Reset Mode button set Park Brake turn key switch to on TBB6002 Page 6-3

Retrieving Active Fault Codes Using the Reset/Mode Button Push/Release diag diagnostics #faults Push/Hold Fault first Push/Release MID# Module Identifier Push/Release PID/SID# Parameter Subsystem Push/Release FMI# Failure Mode second Retrieving active fault codes Fault codes have three components These components are SAE formatted You must retrieve all 3 components of each fault code before they can be interpreted. The Mid is the module identifier or the system reporting the fault The PID or SID is the system’s area of concern like coolant, oil, fuel, injectors The FMI is the failure mode identifier- what is wrong electrically like short, open Always us the reporting system’s information to interpret a fault code The dash button have two positions; push and hold , push and release TBB6002 Page 6-4

Hands-on Activity Using the ICU Dash Retrieve the Active Fault Codes MID___________ SID/PID________ FMI___________ Using Drawing Translate the codes ______________________________ _______________________________ Retrieving active fault codes Hands-on activity Bug the bus causing two active faults Have each student retrieve and then translate the codes using drawing Not all codes are in the drawing so confirm example TBB6002 Page 6-5

Section 7 Evaluation TBB6002 Page

Training Evaluation 1. Student manuals and handouts were?
Class:__________________________ Date:___________ Instructor: _____________________ Please circle the number on each scale which most closely reflects your opinion 1. Student manuals and handouts were? Excellent Good Poor 2. Overheads, presentations, and video tapes were? 3. Shop demonstrations were? 4. The length of the course was? Too Long Just Right Too Short 5. The pace of the presentation was? Too Fast Just Right Too Slow 6. The amount of shop time was? Too Much Just Right Not Enough

Training Evaluation page 2
Please circle the number on each scale which most closely reflects your opinion 7. Did the class provide the expected instruction? Yes Somewhat No Comments:_______________________________ ________________________________________ 8. Would you recommend this class to others? Definitely To Some No 9. Do you feel that what you’ve learned will help you do your job better? Help A Lot Help Some No Help 10. What was your overall impression of the course? Excellent Good Poor 11. If you were to make changes, what would they be? ___________________________________________ Thanks for attending our class

Thomas Built Buses TBB 6002 Saf-T-Liner HDX Chassis Electrical

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Thomas Built Buses TBB 6002 Saf-T-Liner HDX Chassis Electrical

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Presentation on theme: "Thomas Built Buses TBB 6002 Saf-T-Liner HDX Chassis Electrical"— Presentation transcript:

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