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Inlet Air Heater

Inlet Air Heater Lamp Connector P40

Intake Manifold Air Temperature Sensor

Boost Pressure Sensor

Unit Injector Cylinder #6

Coolant Temperature Sensor 1

2

3

4

5

6

High Pressure Pump

Injector Harness Grommet

Injection Actuation Pressure Control Valve (IAPCV)

Injection Actuation Pressure Sensor

Engine Oil Temperature Sensor

Electronic Control Module (ECM) Timing Calibration Probe Connector J24/P24

3126 Truck Engine Electrical System

1BW1-UP

SENR9628 November 2001

© 2001 Caterpillar All Rights Reserved

Injection Actuation Pressure Control Valve (IAPCV)

Engine Oil Temperature Sensor

Injection Actuation Pressure Sensor

Intake Manifold Air Temperature Sensor

Injector Harness Grommet

High Pressure Pump Ground Stud

Top Speed/Timing Sensor

Timing Calibration Probe Connector J24/P24 *

*

Bottom Speed/Timing Sensor

Printed in U.S.A.

ECM Ground Strap

LEFT SIDE VIEW

Electronic Control Module (ECM) ECM Vehicle Harness Connector J1/P1

ECM Engine Harness Connector J2/P2

A B

A701-GY A721-WH

A B

J29 P29

A702-PU A722-YL

A B

J30 P30 CYL NO.1

A703-BR A723-OR

J31 P31 CYL NO.2

A B

A704-GN A724-WH

A B

J32 P32 CYL NO.3

A705-BU A725-YL

A B

J33 P33 CYL NO.4

CYL NO.5

ENGINE SPEED / TIMING ENGINE SPEED / TIMING +

BOTTOM SPEED/TIMING SENSOR

ENGINE SPEED / TIMING ENGINE SPEED / TIMING +

A B

J9

E963-BK E964-WH

1 2

A D797-PK B D798-BK J36 P36

E963-BK E964-WH

P9 A B

J4

E965-BU E966-YL

E965-BU E966-YL A746-PK D841-GN 995-BU C967-BU E795-YL

P4

BOOST PRESSURE SENSOR

BOOST PRESSURE SENSOR COMMON +5V

GN YL OR

INJECTION ACTUATION PRESSURE SENSOR

INJ ACTUATION PRESS. SENSOR COMMON +5V

GN YL OR

C A746-PK B 993-BR A 997-OR P3 J3

993-BR 997-OR

D796-OR C B A

ENG SP/TMG #1ENG SP/TMG #1+

ENG SP/TMG #2ENG SP/TMG #2+ BOOST PRESSURE INJ ACTUATION PRESS. COOLANT TEMP INTAKE MANF AIR TEMP OIL TEMP

SENSOR COMMON +5V

INLET AIR HEATER

COOLANT TEMP SENSOR COMMON +5V

WH BK OR

C B A

995-BU 993-BR 997-OR

INLET AIR HEATER RELAY J37 P37 D812-RD 1 D796-OR 2

INTAKE MANF AIR TEMP SENSOR COMMON +5V

WH BK OR

C B A

C967-BU 993-BR 997-OR

N/O

D812-RD D796-OR

(+) BATTERY SUPPLY WIRES

INJECTOR 1 INJECTOR COMMON 1 INJECTOR 2 INJECTOR COMMON 2 INJECTOR 3 INJECTOR COMMON 3 INJECTOR 4 INJECTOR COMMON 4 INJECTOR 5 INJECTOR COMMON 5 INJECTOR 6 INJECTOR COMMON 6 VEHICLE SPEED OUT+ VEH SP IN+/TDC PROBE+ VEH SP IN-/TDC PROBEVEHICLE SPEED OUTINJ ACTUATION PRESS. CONT VALVE IAP CONT VALVE COMMON

P35 J35

J21 P21

ENGINE OIL TEMPERATURE SENSOR

6 5 12 11 18 17 22 21 28 27 34 33 40 39 4 10 19 13 1 8 9 37 29 25 15 3 23 24 14 2 32 7 16 26 30 36 38 20 35 31

D841-GN 993-BR 997-OR

J10 P10

INTAKE MANIFOLD AIR TEMPERATURE SENSOR

A701-GY A721-WH A702-PU A722-YL A703-BR A723-OR A704-GN A724-WH A705-BU A725-YL A706-GY A726-OR D784-BU D810-PU D811-YL D785-GN D797-PK D798-BK

J24 P24 TIMING CALIBRATION PROBE CONNECTOR

INJECTION ACTUATION PRESSURE CONTROL VALVE

CYL NO.6

TOP SPEED/TIMING SENSOR

COOLANT TEMPERATURE SENSOR

A706-GY A726-OR

J34 P34

ELECTRONIC CONTROL MODULE (ECM)

P2 J2

INJECTOR HARNESS GROMMET

ENGINE OIL TEMP SENSOR COMMON +5V

WH BK OR

C B A

E795-YL 993-BR 997-OR

INLET AIR HEATER

J51 P51

INPUT SIGNAL WIRES TO ECM OUTPUT SIGNAL WIRES FROM ECM

TO +BATTERY

SENSOR SUPPLY VOLTAGE SIGNAL PLUS

TO ENGINE CYL HEAD (NOT CYL HEAD GND STUD)

SIGNAL MINUS

INLET AIR HEATER GROUND STRAP

(-) BATTERY / SENSOR RETURN

469 468

TO POWER PACK INTERFACE

C B K L M N P R S T U V W X Y Z E A A F B C D D E F G H J

C B K L M N P R S T U V W X Y Z E A A F B C D D E F G H J

469 468

B A APC

ECM GND STRAP

P40 B D796-OR A D812-RD

TO ECM MOUNTING BOLT

469 468

LAV B A

CONNECTED TO LAV HARNESS OR APC HARNESS

LAV INTERFACE HARNESS 35 30 37 40 38 14 2 29 22 7 1 18 5 28 4 6

570 571 572 573 574 575 89 577 578 586 585 579 581 580 581 580

3 8 9 10 11 12 13 15 16 17 19 20 21 23 24 25 26 27 31 32 33 34 36 39

TO VEHICLE COMPONENTS

J2 P1

ENGINE BULKHEAD

P6

+8V MULTI-FUNCTION SENSOR COMMON THROTTLE POSITION EXHAUST BRAKE XMSN NEUTRAL SW SERVICE BRAKE SW #1 FAST IDLE ENABLE SW SENSOR COMMON CHECK ENGINE LAMP ATA DATA LINK+ (J1587) ATA DATA LINK- (J1587) VEHICLE SPEED IN+ -BATTERY +BATTERY -BATTERY +BATTERY

FROM (J1) ELECTRONIC CONTROL MODULE (ENGINE)

C B K L M N P R S T U V W X Y Z e A a f b c D d E F G H J

TO POWER PACK INTERFACE J1

C B K L M N P R S T U V W X Y Z e A a f b c D d E F G H J

469 468

APC INTERFACE HARNESS 35 30 37 40 38 14 2 29 22 7 1 18 5 28 4 6

570 571 572 573 574 575 576 577 578 142 151 579 581 580 581 580

+8V MULTI-FUNCTION SENSOR COMMON THROTTLE POSITION EXHAUST BRAKE XMSN NEUTRAL SW SERVICE BRAKE SW #1 FAST IDLE ENABLE SW SENSOR COMMON CHECK ENGINE LAMP ATA DATA LINK+ (J1587) ATA DATA LINK- (J1587) VEHICLE SPEED IN+ -BATTERY +BATTERY -BATTERY +BATTERY

3 8 9 10 11 12 13 15 16 17 19 20 21 23 24 25 26 27 31 32 33 34 36 39

TO VEHICLE COMPONENTS

J1 P1

POWER PACK BULKHEAD

P1

FROM (J1) ELECTRONIC CONTROL MODULE (ENGINE)

J1

35 30 37 40 38 14 2 29 22 7 1 18 5 28 4 6 3 8 9 CONNECTED TO 10 LAV HARNESS OR 11 APC HARNESS 12 13 15 16 17 19 20 21 23 24 25 26 27 31 32 33 34 36 39

+8V MULTI-FUNCTION SENSOR COMMON THROTTLE POSITION EXHAUST BRAKE XMSN NEUTRAL SW SERVICE BRAKE SW #1 FAST IDLE ENABLE SW SENSOR COMMON CHECK ENGINE LAMP ATA DATA LINK+ (J1587) ATA DATA LINK- (J1587) VEHICLE SPEED IN+ -BATTERY +BATTERY -BATTERY +BATTERY NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT

USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED

J1

ELECTRONIC CONTROL MODULE (ECM)

B A

Inlet Air Heater

Inlet Air Heater Relay

Inlet Air Heater Ground Strap

RIGHT SIDE VIEW

SENR9525 November 1999

Electronic Service Tool Will Not Communicate with the ECM

Engine Pressure Sensor Open or Short Circuit Test Connect Electronic Service Tool to Cab Data Link and check for ACTIVE 5 Volt Sensor Supply Code.

ACTIVE Supply Code

NO ACTIVE Supply Codes

Engine Temperature Sensor Open or Short Circuit Test Connect an Electronic Service Tool and check for an ACTIVE Engine Temperature Sensor OPEN or SHORT Circuit Code. If the code is not ACTIVE and the Engine is not running properly, refer to Troubleshooting Without A Diagnostic Code.

Refer to +5Volt Pressure Sensor Supply Voltage Circuit Test

Check Electrical Connectors and Wiring. Active SHORT Circuit Code Turn the ignition key ON, engine OFF. Disconnect the Sensor Connector with the ACTIVE Short Circuit Code in order to create an Open Circuit condition. Code Changes To OPEN Circuit

SHORT Circuit Code Remains

If a Short Circuit code was Active before the sensor was disconnected and an Open Circuit code became Active after the sensor was disconnected then thoroughly inspect the connector for signs of moisture. Inspect the seals and connect the sensor. If the code reappears, the sensor or pigtail harness is the problem. Temporarily connect a new sensor but do not install it into the engine. If the code is no longer Active with the new sensor connected, replace the old sensor.

Check Electrical Connectors and Wiring. NOT OK

Active SHORT Circuit Code

Refer to Inspecting Electrical Connectors

Active OPEN Circuit Code Measure Sensor Supply Voltage with multimeter. Reading should be within 4.5 to 5.5 VDC range. Supply OK

NOT OK Refer to +5Volt Engine Pressure Sensor Supply Voltage Circuit Test

Install a short circuit between terminal-B and terminal-C of the Sensor Connector and check for an ACTIVE Short Circuit code. OPEN Circuit Code Active with jumper

SHORT Circuit Code Active with jumper

OK Remove the sensor signal wire from ECM connector P2 and the sensor connector. Bypass the signal wiring by connecting a jumper wire directly from ECM connector P2 to the sensor connector signal terminal. If the Diagnostic Code disappears with the bypass wire installed, repair or replace the harness. Otherwise, restart the test procedure.

With the ignition key ON and engine OFF, Disconnect the Sensor Connector with the ACTIVE Short Circuit Code in order to create an Open Circuit condition. Code Changes To OPEN Circuit

NOT OK If the OPEN Circuit code is NOT Active with the harness disconnected, or the SHORT Circuit code is NOT Active with the jumper (short) installed, temporarily install a test ECM. If the test ECM resolves the problem, install the old and verify problem returns. If the test ECM works and the original ECM does not, replace the ECM.

SHORT Circuit Code Remains

If a Short Circuit code was Active before the sensor was disconnected and an Open Circuit code became Active after the sensor was disconnected then thoroughly inspect the connector for signs of moisture. Inspect the seals and connect the sensor. If the code reappears, the sensor is the problem. Temporarily connect a new sensor but do not install it into the engine. If the code is no longer Active with the new sensor connected, replace the old sensor.

If a SHORT Circuit Code appears, temporarily connect the suspect sensor. If an OPEN Circuit code returns, replace the sensor and verify the diagnostic code does not return.

Disconnect the ECM Connector J2/P2 and check for Active diagnostic codes. The OPEN Circuit code should be Active with the harness disconnected. Install a jumper (short) between the ECM Connector J2 signal terminal and terminal-3. A SHORT Circuit code should be Active with the jumper installed.

Repair Service Tool

OK

Try to start the Engine.

Connect Electronic Service Tool to the Cab data link, turn ignition key switch ON, engine OFF. Attempt to establish communications with the ECM.

Does not start

ECM does not communicate

Engine starts, but ECM does not communicate with the Service Tool

NOT OK

Repair Cables

Refer to Inspecting Electrical Connectors

Disconnect ECM Connector P1 from the ECM. Use the Service Tool Bypass Harness as indicated in the Ignition Key Switch Circuit Test.

With the ignition key On and engine OFF, Install a short circuit between terminal-1 and terminal-2 of the Sensor Connector and check for an ACTIVE Short Circuit code. SHORT Circuit Code Active with jumper

If a SHORT Circuit Code appears, temporarily connect the suspect sensor. If an OPEN Circuit code returns, replace the sensor and verify the diagnostic code does not return.

Connect the Service Tool using a completely different set of Service Tool cables. No Communications

Active OPEN Circuit Code

OPEN Circuit Code Active with jumper

OK

ECM and Service Tool Communicate

3126B Truck Engine Electrical System 6PZ1-UP 7JZ1-UP

No Communications

Either the vehicle wiring or another device on the vehicle is causing the communication problem.

OK Remove the sensor signal wire from ECM connector P2 and the sensor connector. Bypass the signal wiring by connecting a wire directly from ECM connector P2 to the sensor connector signal terminal. If the Diagnostic Code disappears with the bypass wire installed, repair or replace the harness. Otherwise, restart the test procedure.

OK

NOT OK

Refer to the Ignition Keyswitch Circuit Test

Check ECM power, ground, and keyswitch connections with the ignition key switch ON. Battery voltage at ECM Connector J1/P1 terminal-52, 53 and 70, to terminal-65 and 67 should be 11.0 -13.5 VDC for a 12 Volt system and 22.0 - 27.0 for a 24 Volt system. OK

NOT OK Refer to the ECM Memory Test

A new ECM has an unprogrammed Personality Module. The engine will not start or communicate until the Personality Module in the ECM is Flash Programmed. Not a New ECM

Check the Ignition Key Switch status on the Service Tool. With the Ignition Key Switch ON, the status should display ON. If the status displays OFF, check for voltage from the battery. Battery voltage at ECM Connector J1/P1 terminal-70 to terminal-65 and 67 should be 11.0 -13.5 VDC for a 12 Volt system and 22.0 - 27.0 for a 24 Volt system.

Connect a test ECM. Turn the Ignition Key ON, engine OFF. If the new ECM communicates and the old ECM does not, reconnect the old ECM and verify the problem returns. If the new ECM communicates and the old ECM does not, replace the ECM. If the new ECM does not communicate, there is a problem with the cables or the battery.

NOT OK

OK NOT Refer OK to the ECM Memory Test NOT OK

Disconnect the ECM Connector J2/P2 and check for Active diagnostic codes. The OPEN Circuit code should be Active with the harness disconnected. Install a jumper (short) between the ECM Connector J2 signal terminal and terminal-18. A SHORT Circuit code should be Active with the jumper installed.

ECM Communicates

Ensure after-market engine protection devices (not installed by Caterpillar) are not active, preventing the ECM or Ignition Key Switch from receiving battery power.

Connect another Service Tool to the ECM, but use the same Service Tool Cables as in the previous step. No Communications

ACTIVE Open or Short Circuit Code

Check for ACTIVE Engine Pressure Sensor OPEN or SHORT Circuit Code. If the code is not ACTIVE and the Engine is not running properly, refer to Troubleshooting Without A Diagnostic Code. ACTIVE Open or Short Circuit Code

Does not crank, refer to engine will not crank.

Engine Cranks, But Will Not Start

Refer to the Engine Speed/Timing Circuit Test

If the Personality Module has been recently replaced/updated , connect and check for an active 252-11 Incorrect Engine Software.

Refer to the Ignition Keyswitch Circuit Test

OK

Observe engine rpm from Electronic Service Tool while cranking the engine. An rpm value should be displayed on the Service Tool. OK

If the Truck is equipped with a CAT ID , ensure Theft Deterrent is not Active . Turn the Ignition Key Switch ON, engine OFF, the CAT ID will indicate Theft Deterrent Active.

NOT OK If the OPEN Circuit code is NOT Active with the harness disconnected, or the SHORT Circuit code is NOT Active with the jumper (short) installed, temporarily install a test ECM. If the test ECM resolves the problem, install the old and verify problem returns. If the test ECM works and the original ECM does not, replace the ECM.

OK

Monitor the exhaust stack while cranking - if no smoke is present there may be a fuel supply or quality problem. Check fuel pressure, priming, and filters. OK

Check for combustion problems, mechanical problems or extreme temperatures.

NOTE: Refer to the Electronic Troubleshooting Guide for detailed information.

NOTE: Refer to the Electronic Troubleshooting Guide for detailed information.

NOTE: Refer to the Electronic Troubleshooting Guide for detailed information.

© 1999 Caterpillar All Rights Reserved

Printed in U.S.A.

SENR9525-00 8 Page, JVD

NOTE: Refer to the Electronic Troubleshooting Guide for detailed information.

3126B ENGINE HARNESS WIRING DIAGRAM

INTAKE MANIFOLD GROMMET

L983-WH

12 11 10 9 8 7

L983-WH L984-OR L984-OR L985-YL L985-YL J301 P301 B A

J302 P302 B A

INJECTOR CYLINDER NO.1

J303 P303 B A

J304 P304 B A

J305 P305 B A

J306 P306 B A

INJECTOR CYLINDER NO.3

INJECTOR CYLINDER NO.4

INJECTOR CYLINDER NO.5

INJECTOR CYLINDER NO.6

INJECTOR CYLINDER NO.2

A706-GY

ENGINE HARNESS CONNECTOR P2 J2 L983-WH L984-OR L985-YL A706-GY A705-BU A704-GN A703-BR A702-PU A701-GY

6 5 4 3 2 1

44 45 46 55 54 39 38 37 36 47 67 68 1 63 64 4 5 61 62 70 40 27 6 7 14 3 2 15 16 17 24 42 41 25 50 52 53 60 9 32 35 33 34 26 18 10 11 12

P300 J300

A705-BU A704-GN A703-BR A702-PU A701-GY A B

INJECTION ACTUATION PRESSURE CONTROL VALVE

G854-PK G855-PU

J500 P500 GN YL OR

ENGINE BOOST PRESSURE ENGINE PRESSURE SENSOR COMMON ENGINE PRESSURE SENSOR +5V

ENGINE BOOST PRESSURE SENSOR

A746-PK G829-GN G828-WH

C B A

A746-PK G849-BR

J200 P200

GN YL 0R

ENGINE INJECTION ACTUATION PRESSURE SENSOR

ENGINE INJECTION ACTUATION PRESS ENGINE PRESSURE SENSOR COMMON ENGINE PRESSURE SENSOR +5V

ENGINE ATMOSPHERIC PRESSURE SENSOR NOTE A

ENGINE ATMOSPHERIC PRESSURE ENGINE PRESSURE SENSOR COMMON ENGINE PRESSURE SENSOR +5V

C B A

A747-GY G829-GN G828-WH

G849-BR G829-GN G828-WH 994-GY G827-BU G826-BR

P204 J204

GN YL OR

A747-GY G829-GN G828-WH

C B A

P203 J203

ENGINE OIL PRESSURE SENSOR NOTE A

GN YL OR

ENGINE OIL PRESSURE SENSOR ENGINE OIL PRESSURE SENSOR COMMON ENGINE OIL PRESSURE SENSOR +5V

995-BU C967-BU

994-GY G827-BU G826-BR

C B A

G846-YL

P201 J201

G833-PK TOP CAMSHAFT ENGINE SPEED/TIMING SENSOR

ENGINE COOLANT TEMPERATURE ENGINE TEMPERATURE SENSOR COMMON

ENGINE COOLANT TEMPERATURE SENSOR

A B

TOP CAMSHAFT SPEED/TIMINGTOP CAMSHAFT SPEED/TIMING+

995-BU G833-PK

1 2

J100 P100

ENGINE INTAKE MANIFOLD AIR TEMPERATURE SENSOR

ENGINE INTAKE MANIFOLD AIR TEMPERATURE ENGINE TEMPERATURE SENSOR COMMON

ENGINE OIL TEMPERATURE SENSOR

ENGINE OIL TEMPERATURE ENGINE TEMPERATURE SENSOR COMMON

49 48 13 19 20 21 28 29 30 59 58 31 43 51 22 23 56 57 65 66 69 8

BOTTOM CAMSHAFT ENGINE SPEED/TIMING SENSOR

C967-BU G833-PK

1 2

E963-BK E964-WH

J401 P401

J103 P103

E965-BU E966-YL

A B

BOTTOM CAMSHAFT SPEED/TIMINGBOTTOM CAMSHAFT SPEED/TIMING+

J402 P402 G846-YL G833-PK

1 2

ENGINE TIMING CALIBRATION PROBE+ ENGINE TIMING CALIBRATION PROBE-

J101 P101

G856-WH G857-YL

A B

(+) BATTERY SUPPLY WIRES

J400 P400 TO INTAKE AIR HEATER CIRCUIT FUSIBLE PROTECTION

INPUT SIGNAL WIRES TO ECM

K995-OR J501 P501 C987-RD 1 G850-BU 2

OUTPUT SIGNAL WIRES FROM ECM SENSOR SUPPLY VOLTAGE SIGNAL PLUS

(-) BATTERY / SENSOR RETURN

IAP CONTROL VALVE IAP CONTROL VALVE COMMON ENGINE BOOST PRESSURE ENGINE INJECTION ACTUATION PRESSURE

ENGINE ATMOSPHERIC PRESSURE ENGINE PRESSURE SENSOR COMMON ENGINE PRESSURE SENSOR +5V

ENGINE OIL PRESSURE SENSOR ENGINE OIL PRESSURE SENSOR COMMON ENGINE OIL PRESSURE SENSOR +5V ECM GROUND STRAP

TO ECM ENGINE COOLANT TEMPERATURE MOUNTING ENGINE INTAKE MANIFOLD AIR TEMPERATURE BOLT ENGINE OIL TEMPERATURE ENGINE TEMPERATURE SENSOR COMMON

TOP CAMSHAFT SPEED/TIMINGTOP CAMSHAFT SPEED/TIMING+

BOTTOM CAMSHAFT SPEED/TIMINGBOTTOM CAMSHAFT SPEED/TIMING+

ENGINE TIMING CALIBRATION PROBE+ ENGINE TIMING CALIBRATION PROBE-

INTAKE AIR HEATER RELAY

N/O RELAY

TO ENGINE CYLINDER HEAD (NOT CYLINDER HEAD GROUND STUD)

COMPONENTS ARE SHOWN WITH THE KEY OFF UNLESS OTHERWISE SPECIFIED: ALL WIRES TO BE 18 AWG OR LARGER SAE J1560 TYPE TXL OR EQUIVALENT. FOR TWISTED PAIR SPECIFICATION SEE SAE J1708

SIGNAL MINUS

G850-BU

INJECTOR COMMON CYLINDERS 1 & 2 INJECTOR COMMON CYLINDERS 3 & 4 INJECTOR COMMON CYLINDERS 5 & 6 INJECTOR CYLINDER 6 INJECTOR CYLINDER 5 INJECTOR CYLINDER 4 INJECTOR CYLINDER 3 INJECTOR CYLINDER 2 INJECTOR CYLINDER 1

P1 J1

INTAKE AIR HEATER

P648 G850-BU C987-RD

B A

TO CONNECTOR J648

VEHICLE HARNESS CONNECTOR NOTE A: A DASHED LINE SPECIFIES AN OPTIONAL FEATURE, NOT AVAILABLE ON ALL SYSTEMS.

3126B VEHICLE HARNESS WIRING DIAGRAM

INTAKE AIR HEATER LAMP

TO INTAKE AIR HEATER RELAY

100A WITH 130A PEAK AT 11V

TO CONNECTOR P648

B A

(CONTACT SIDE) C987-RD

J648 ENGINE HARNESS CONNECTOR

CIRCUITS WITHIN THIS AREA ARE RECOMMENDATIONS CHECK ENGINE LAMP C987-RD

K995-OR

N/O RELAY

L994-YL P2 J2

WARNING LAMP

OFF ON START

659-PK L994-YL K998-BU G880-PK

659-PK

FAST IDLE ENABLED LAMP

NOTE A

G880-PK

EXHAUST BRAKE ON/OFF SWITCH

EXHAUST BRAKE SOLENOID

KEY SWITCH

FLYBACK DIODE

E718-PK E991-GY G836-WH

NOTE A

SPEEDOMETER NOTE A

SIGNAL+

C974-PU

SIGNAL-

C973-GN

STARTER MOTOR (12V)

ALTERNATOR GROUND

C E D F J1587 DATA LINK NEGATIVE B E793-BU J1587 DATA LINK POSITIVE A E794-YL TO J1939 DATA LINK CONNECTOR TO J1939 DATA LINK CONNECTOR TO J1939 DATA LINK CONNECTOR +BAT. -BAT.

- 12V +

BATTERY 3

- 12V +

- 12V +

BATTERY 2

C974-PU C973-GN NOTE A

CAB DIAGNOSTIC CONNECTOR

BATTERY 1

NOTE A

TACHOMETER NOTE A

SIGNAL+

450-YL

SIGNAL-

451-BR

993-BR F713-OR 450-YL 451-BR NOTE A E793-BU E794-YL A249-BK K990-GN K900-YL

NOTE A

TO ALLISON AT/MT SHIFT MODULATOR FOR MECHANICAL TRANSMISSION

J906-BR 14 AWG GXL 14 AWG GXL 14 AWG GXL 14 AWG GXL

20A ENGINE BLOCK

101-RD 101-RD 229-BK 229-BK G838-BR G839-BU

NOTE A C978-BR C979-OR

H795-PK

SET/RESUME

H795-PK

C978-BR C979-OR K999-GN K980-PK L902-GN G840-PU C975-WH K982-YL G841-GN C992-PU

FAST IDLE ENABLE SWITCH

NOTE A

H795-PK

N/O MOMENTARY SWITCH

L902-GN

C975-WH

CRUISE CONT ON/OFF

SERVICE BRAKE PEDAL POSITION N/C H795-PK (PEDAL RELEASED POSITION)

C992-PU SERVICE BRAKE PEDAL POSITION #2 N/O +BAT. G882-WH

CLUTCH PEDAL POSITION N/C H795-PK (PEDAL RELEASED POSITION)

G842-GY G882-WH G843-OR L901-GY C977-BU

(PEDAL RELEASED POSITION) NOTE A

NOTE A

C977-BU

DIAGNOSTIC ENABLE SWITCH NOTE A

SENR9525-00

8 Page, Color 2, JVD

29 28 30 31 48 61 10 12 13 15 16 63 36 37 27 26 3 17 38 39 57 43 9 8 42 34 50 1 14 70 25 52 53 65 67 19 20 51 35 44 56 58 40 21 59 60 7 45 55 47 64 6 18 22 23 2 46 49 54 62 24 41 69 32 33 68 5 4 66 11

H795-PK

N/O MOMENTARY SWITCH

A/C HIGH PRESS. SWITCH N/C NOTE A

G879-OR G844-PK C983-WH C984-YL 409-OR

G844-PK +BAT.

TRANSMISSION NEUTRAL N/O (TRANSMISSION IN GEAR) NOTE A

409-OR

E971-GN

H795-PK

E971-GN PASSIVE MAGNETIC VEHICLE SPEED SENSOR

COMPONENTS WITHIN THIS AREA ARE CATERPILLAR PROVIDED ACCELERATOR PEDAL SENSOR/SWITCH SENSOR COMMON +8 V ACCELERATOR PEDAL POSITION

B A C

BK RD WH

1 2

G808-BU G809-GN G845-PU H795-PK C985-BU C986-BR G837-YL

H795-PK C985-BU C986-BR

J403 P403

SENSOR ACCELERATOR PEDAL POSITION

G808-BU G809-GN

COOLING FAN SOLENOID NOTE A

FLYBACK DIODE

WARNING LAMP CHECK ENGINE LAMP OUTPUT #1 OUTPUT #9

OUTPUT #2 OUTPUT #3 OUTPUT #4

SPEEDOMETER POSITIVE SPEEDOMETER NEGATIVE

INPUT SENSOR COMMON #2 INPUT #14 TACHOMETER POSITIVE TACHOMETER NEGATIVE

J1587 DATA LINK NEGATIVE J1587 DATA LINK POSITIVE J1939 DATA LINK SHIELD J1939 DATA LINK NEGATIVE J1939 DATA LINK POSITIVE

IGNITION KEY SWITCH UNSWITCHED +BATTERY UNSWITCHED +BATTERY -BATTERY -BATTERY OUTPUT #6 OUTPUT #7 SET RESUME INPUT #1 INPUT #2 INPUT #18 OUTPUT #8 CRUISE CONTROL ON/OFF SWITCH INPUT #3 INPUT #4 SERVICE BRAKE PEDAL POSITION SWITCH INPUT #5 INPUT #13 INPUT #6 INPUT SENSOR COMMON #1 CLUTCH PEDAL POSITION SWITCH +5V INPUT #7 ENGINE COOLANT LEVEL NORMAL ENGINE COOLANT LEVEL LOW INPUT #12 INPUT #11 VEHICLE SPEED IN POSITIVE VEHICLE SPEED IN NEGATIVE INPUT #8 AP SENSOR/SWITCH SENSOR COMMON +8V ACCELERATOR PEDAL POSITION OUTPUT #5

P1 J1 VEHICLE HARNESS CONNECTOR

NOTE A: A DASHED LINE SPECIFIES AN OPTIONAL FEATURE, NOT AVAIL ABLE ON ALL SYSTEMS.

ECM AMP Connectors

13

1

23

14

31

24

39 47

32 40

57 70

48 58

1

2

3

4

5

6

8

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