©2001 C

aterpillarAll R

ights Reserved

Printed in U.S.A.

SENR

9628N

ovember 2001

3126 Truck E

ngineE

lectrical System

1BW

1-UP

TOP VIEW

LEFT SIDE VIEW

ECMGroundStrap

Electronic ControlModule (ECM)

Electronic ControlModule (ECM)

ECM EngineHarnessConnectorJ2/P2

ECM VehicleHarnessConnectorJ1/P1

InjectorHarnessGrommet

TimingCalibrationProbeConnectorJ24/P24

Timing CalibrationProbe ConnectorJ24/P24

InjectorHarnessGrommet

InjectionActuationPressureSensor

GroundStud

InjectionActuationPressureSensor

Intake ManifoldAir TemperatureSensor

UnitInjectorCylinder #6

654321

Intake ManifoldAir TemperatureSensor

Engine OilTemperatureSensor

Engine OilTemperatureSensor

HighPressurePump

HighPressurePump

BoostPressureSensor

CoolantTemperatureSensor

Injection ActuationPressure ControlValve (IAPCV)

Injection ActuationPressure ControlValve (IAPCV)

TopSpeed/TimingSensor

BottomSpeed/TimingSensor

*

*

Inlet Air HeaterLamp ConnectorP40

Inlet AirHeater

INPUT SIGNAL WIRES TO ECM

OUTPUT SIGNAL WIRES FROM ECM

SENSOR SUPPLY VOLTAGE

(+) BATTERY SUPPLY WIRES

SIGNAL PLUS

(-) BATTERY / SENSOR RETURN

SIGNAL MINUS

P2 J2

J51 P51

CBA

ENGINE OILTEMPERATURE

SENSOR

E795-YL993-BR997-OR

ENGINE OIL TEMPSENSOR COMMON

+5V

WHBKOR

INTAKE MANF AIR TEMPSENSOR COMMON

+5V

J10 P10

C967-BU993-BR997-OR

INTAKE MANIFOLDAIR TEMPERATURE

SENSOR ABC

WHBKOR

N/O

RELAYJ37

J36 P36

J24 P24J34 P34

J33 P33

J32 P32

J31 P31

J30 P30

J29 P29

BOOST PRESSURESENSOR COMMON

+5V

BOOSTPRESSURE

SENSOR

INJECTIONACTUATIONPRESSURE

SENSOR

CYLNO.1

CYLNO.2

CYLNO.3

CYLNO.4

CYLNO.5

A706-GYA726-OR

A705-BUA725-YL

A704-GNA724-WH

CBA

A746-PK993-BR997-OR

12

P3 J3

INJECTION ACTUATION

TIMING CALIBRATIONPROBE CONNECTOR

PRESSURE CONTROL VALVEAB

INLET AIRHEATER

INLET AIRHEATERGROUND STRAP

INLET AIRHEATER

E965-BUE966-YL

CYLNO.6

E963-BKE964-WH

TO ENGINE CYL HEAD(NOT CYL HEAD GND STUD)

TO +BATTERY

21

A703-BRA723-OR

A702-PUA722-YL

BA

BA

AB

AB

AB

AB

AB

WHBKOR

INJECTOR HARNESS GROMMET

D796-ORD812-RD

469468

GNYLOR

TO ECM

MOUNTING

BOLT

D797-PKD798-BK

65

12111817222128273433

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

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

ECM GND STRAP

ELECTRONIC CONTROL MODULE (ECM)

ELECTRONIC CONTROL MODULE (ECM)

ENG SP/TMG #2-ENG SP/TMG #2+BOOST PRESSUREINJ ACTUATION PRESS.COOLANT TEMPINTAKE MANF AIR TEMPOIL TEMP

SENSOR COMMON+5V

INLET AIR HEATER

372925153

2324142

327

1626303638203531

40394

101913189

A

INJ ACTUATION PRESS.SENSOR COMMON

+5V

GNYLOR

B

TOP SPEED/TIMING SENSOR ENGINE SPEED / TIMING -ENGINE SPEED / TIMING +

ENGINE SPEED / TIMING -ENGINE SPEED / TIMING +

P35 J35

J9 P9

A701-GYA721-WH

J4 P4

B

D841-GN993-BR997-ORA

BC

A

A701-GYA721-WHA702-PUA722-YLA703-BRA723-ORA704-GNA724-WHA705-BUA725-YLA706-GYA726-ORD784-BUD810-PUD811-YLD785-GND797-PKD798-BK

E963-BKE964-WH

COOLANT TEMPSENSOR COMMON

+5V

995-BU993-BR997-OR

COOLANTTEMPERATURE

SENSOR ABC

D812-RDD796-OR

D812-RD

D796-OR

BOTTOM SPEED/TIMING SENSOR

P40

APCCONNECTED TOLAV HARNESS ORAPC HARNESS

LAV

P37

J21 P21

E965-BUE966-YLA746-PKD841-GN995-BU

C967-BUE795-YL

993-BR997-OR

D796-OR

AB

J1

P6 J1

P1J2

P1 J1

P1J1

469468

BA

35 +8V30 MULTI-FUNCTION SENSOR COMMON37 THROTTLE POSITION

EXHAUST BRAKE40XMSN NEUTRAL SW38SERVICE BRAKE SW #114

2 FAST IDLE ENABLE SW29 SENSOR COMMON

CHECK ENGINE LAMP227 ATA DATA LINK+ (J1587)1 ATA DATA LINK- (J1587)

VEHICLE SPEED IN+185 -BATTERY

28 +BATTERY4 -BATTERY6 +BATTERY

3 NOT USED8 NOT USED9 NOT USED

11 NOT USED10 NOT USED

12 NOT USED13 NOT USED15

FROM (J1)ELECTRONIC

CONTROL MODULE(ENGINE)

FROM (J1)ELECTRONIC

CONTROL MODULE(ENGINE)

NOT USED16 NOT USED17 NOT USED19 NOT USED20 NOT USED21 NOT USED23 NOT USED24 NOT USED25 NOT USED26 NOT USED27 NOT USED31 NOT USED32 NOT USED33 NOT USED34 NOT USED36 NOT USED39 NOT USED

+8VMULTI-FUNCTION SENSOR COMMON

LAV INTERFACE HARNESS

THROTTLE POSITIONEXHAUST BRAKEXMSN NEUTRAL SWSERVICE BRAKE SW #1FAST IDLE ENABLE SWSENSOR COMMONCHECK ENGINE LAMPATA DATA LINK+ (J1587)ATA DATA LINK- (J1587)VEHICLE SPEED IN+-BATTERY+BATTERY-BATTERY+BATTERY

570 35571

469468

30572 37573 40574 38

1457589 2577 29

22578586 7585 1

18579581 5580 28581 4580 6

KLMNPRSTUVWXYZEAAFBCD

TO VEHICLECOMPONENTS

TOPOWER PACKINTERFACE

ENGINEBULKHEAD

DEFGHJ

KLMNPRSTUVWXYZEAAFBCDDEFGHJ

389

1110

12131516171920212324252627313233343639

+8VMULTI-FUNCTION SENSOR COMMON

APC INTERFACE HARNESS

THROTTLE POSITIONEXHAUST BRAKEXMSN NEUTRAL SWSERVICE BRAKE SW #1FAST IDLE ENABLE SWSENSOR COMMONCHECK ENGINE LAMPATA DATA LINK+ (J1587)ATA DATA LINK- (J1587)VEHICLE SPEED IN+-BATTERY+BATTERY-BATTERY+BATTERY

570 35571 30572 37573 40574 38

14575576 2577 29

22578142 7151 1

18579581 5580 28581 4580 6

KLMNPRSTUVWXYZeAafbcD

TO VEHICLECOMPONENTS

TOPOWER PACKINTERFACE

POWER PACKBULKHEAD

d

BC

EFGHJ

KLMNPRSTUVWXYZeAafbcDd

BC

EFGHJ

389

1110

12131516171920212324252627313233343639

BC

BC

469468

RIGHT SIDE VIEW

Inlet AirHeaterRelay

Inlet AirHeaterGroundStrap

Inlet AirHeater

AB

CONNECTED TOLAV HARNESS ORAPC HARNESS