Caterpillar 3126 Plano

RENR1368-05 September 2005

ECM Connectors

Diagnostic Code Listing 6 HEUI Injectors

Engine Control Module

P ID -F MI

Cab Diagnostic Connector

- 12 V +

Batteries

ECM Side

ECM Connector P1

Cruise Control On/Off & Set/Resume Switches

Harness Side

Accelerator Pedal Position Sensor

Injection Actuation Pressure Control Valve (IAPCV)

Ignition Key Switch Clutch and Service Brake Switches

Top Camshaft Speed/Timing Sensor Coolant Level Sensor C a t e r p i l l a r I n s t a l l e d

Bottom Camshaft Speed/Timing Sensor

ECM Side

ECM Connector P2

Harness Side Injection Actuation Pressure Sensor

D T C on on ne ne ct ct or or R ec ec ep ep ta ta cl cl e

d e l l a t s n I

Check Engine Lamp

WarningLamp

3126B and 3126E On-highway Engines Electrical System

M E O

Speedometer&Tachometer

D T C on on ne ne ct ct or or P lu g

45 3

5

15 5

5

20

25

Boost Pressure Sensor

65

15

10

75

5

25

5 0

Atmospheric Pressure Sensor

Receptacle Wedge

MPH

85

A/C High Pressure Switch

BKD1-UP G3E1-UP 1AJ1-UP 8YL1-UP CKM1-UP CRP1-UP 7AS1-UP 8SZ1-UP 9SZ1-UP

Cooling Fan

Vehicle Speed Sensor Oil Pressure Sensor PTO Accelerator Position Sensor (Optional)

Fast Idle Enabled Lamp Or Wait To Start Lamp

Receptacle Wedge Plug Wedge

HD Connector Receptacle

PTO Switch On Lamp

Oil Level Switch

HD Connector Plug

(Optional)

PTO On/Off & PTO Set/ResumeSwitches

Fast Idle Enable Switch

CoolantTemperatureSensor

Flash Codes

P ID -F MI

55

0 10 5- 03

D es cr ip ti on IntakeManifoldAirTemperaturevoltagehigh

72

0 10 5- 04

IntakeManifoldAirTemperaturevoltagelow

38

72

0 10 5- 11

VeryHighIntakeManifoldAir Temperature

64

0003-11

Cylinder#3Injectorcurrentfault

73

0 10 8- 03

BarometricPressurevoltagehigh

26

0004-11


73

0 10 8- 04

BarometricPressurevoltagelow

26

0005-11


74

0 11 0- 00

HighCoolantTemperatureWarning

61

0006-11


74

0 11 0- 03

CoolantTemperaturevoltagehigh

27

0022-11

PrimarytoSecondaryEngine SpeedSignalCalibration

42

0 11 0- 04

CoolantTemperaturevoltagelow

27

0022-13

EngineSpeedSignalCalibrationNotPerformed

42

0 11 0- 11

VeryHighCoolantTemperature

61

0030-08

PTOThrottlesignalinvalid

29

0 11 1- 01

LowCoolantLevelWarning

62

0030-13

PTO Throttle out of calibration

29

0 11 1- 02

CoolantLevelsignalinvalid

12

0041-03

8VoltSupplyvoltagehigh

21

0 11 1- 03

CoolantLevelvoltagehigh

12

21

0 11 1- 04

CoolantLevelvoltagelow

12

0111-11

VeryLowCoolantLevel

62

0041-04

8 Volt Supply voltage low

0042-11

InjectionActuationPressureoutputfault

0043-02

Key Switch Fault

71

0 12 8- 03

SecondaryFuelLevelvoltagehigh

0064-02

SecondaryEngineSpeedlossofsignal

34

0 12 8- 04

SecondaryFuelLevelvoltagelow

0064-11

SecondaryEngineSpeednopattern

34

0 16 4- 00

ExcessiveInjectionActuationPressure

Inlet Air Heater current low

0164-02

InjectionActuationPressureSignalErratic

15

Inlet Air Heater current high

0164-03

InjectionActuationPressurevoltagehigh

15

0071-00

IdleShutdownOverride

01

0 16 4- 04

InjectionActuationPressurevoltagelow

15

0071-01

IdleShutdown

47

0 16 4- 11

InjectionActuationPressuresystemfault

39

0071-14

PTOShutdown

47

0 16 8- 02

ECMBatteryPower Intermittent

51

0084-00

VehicleOverspeedWarning

41

0 18 6- 14

PTOEngineShutdownSwitchOccurrence

47

0084-01

VehicleSpeedlossofsignal

31

0 19 0- 00

EngineOverspeedWarning

35

0084-02

VehicleSpeedsignalinvalid

36

0 19 0- 02

PrimaryEngineSpeedLossofSignal

34

0084-08

VehicleSpeedsignaloutofrange

0190-11

PrimaryEngineSpeednopattern

0084-10

VehicleSpeedsignalrateofchange

36

0 22 4- 11

Theft Deterrent Active

0091-08

ThrottlePositionInvalid

32

0 22 4- 14

Theft Deterrent Active with Engine Cranking

Transmission Neutral Switch

0091-13

ThrottlePositionoutof calibration

28

0 23 1- 02

J1939DataIncorrect

58

0096-03

FuelLevelvoltagehigh

0231-11

J1939 Data Link Fault

58

0096-04

FuelLevelvoltagelow

0231-12

J1939DeviceNotResponding

0100-03

OilPressurevoltagehigh

24

0 23 2- 03

5VoltSupplyvoltagehigh

21

0100-04

OilPressurevoltagelow

24

0 23 2- 04

5 Volt Supply voltage low

21

0100-11

Very Low Oil Pressure

46

0 24 6- 11

Brake Pedal Switch #1 Fault

0102-03

BoostPressurevoltagehigh

25

0 24 7- 11

Brake Pedal Switch #2 Fault

0102-04

BoostPressurevoltagelow

25

0 25 2- 11

EngineSoftwareIncorrect

59

0102-07

BoostPressurenot responding

0253-02

Check Customer or System Parameters

56

0105-00

HighIntakeManifoldAirT emperatureWarning

0 25 3- 14

TruckManufacturerParameterNotProgrammed

64

Related Electrical Service Manuals Title

Sealing Plug

Intake Air Heater Relay

Exhaust Brake Exhaust Brake On/Off Switch

Speed/Timing Sensor Connectors

IAPCV Connector

RENR1367

SystemsOperation/TestingandAdjusting

RENR1271

A

150 Series Receptacle

150 Series Plug © 2005Caterpillar All Rights Reserved

Printed in U.S.A.

RENR1368-05 8 Page

3126B & 3126E ENGINE ELECTRICAL SCHEMATIC

INJECTOR HARNESS GROMMET

L983-WH

12 11

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

J302 P302

B A

J303 P303

J304 P304

J305 P305

J306 P306

B A

B A

B A

B A

B A

ENGINE HARNESS CONNECTOR ENGINE CONTROLMODULE

10 9 8 7

L984-OR

A706-GY

P2 J2

6 5 4 3 2 1

INJECTOR

INJECTOR

INJECTOR

INJECTOR

INJECTOR

CYLINDER NO.1

CYLINDER NO.2

CYLINDER NO.3

CYLINDER NO.4

CYLINDER NO.5

INJECTOR

L983-WH L984-OR

44 45

INJECTOR RETURN CYLINDERS 1 & 2 INJECTOR RETURN CYLINDERS 3 & 4

L985-YL A706-GY A705-BU A704-GN A703-BR A702-PU A701-GY

46 55 54 39 38 37 36 47 67

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

P300 J300

CYLINDER NO.6

68

A705-BU

1 63 64 4 5

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

INJECTIONACTUATION PRESSURE CONTROLVALVE (IAPCV) ENGINE BOOST PRESSURE ENGINE BOOST PRESSURE

C B A

ENGINE PRESSURE SENSOR RETURN ENGINE PRESSURE SENSOR +5V

SENSOR

G854-PK G855-PU

J500 P500

A746-PK G829-GN G828-WH

A746-PK G849-BR

C200

A747-GY G829-GN G828-WH

ENGINE INJECTION ACTUATION PRESSURE SENSOR

ENGINE INJECTIONACTUATION PRESSURE

C B A


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

C204

ENGINEATMOSPHERIC PRESSURE SENSOR NOTEA

ENGINEATMOSPHERIC PRESSURE

C

A747-GY

ENGINE PRESSURE SENSOR RETURN

B A

G829-GN G828-WH

ENGINE PRESSURE SENSOR +5V

C203

ENGINE OIL PRESSURE SENSOR NOTEA

ENGINE OILPRESSURE SENSOR ENGINE OILPRESSURE SENSOR RETURN ENGINE OILPRESSURE SENSOR +5V

G883-GN G458-GY 994-GY G827-BU G826-BR

C201

G833-PK

ENGINEOILLEVELRETURN

1

G458-GY G829-GN

2

TOP CAMSHAFT SPEED/TIMINGTOP CAMSHAFT SPEED/TIMING+

J802 P802

A B

E963-BK E964-WH

ENGINE COOLANTTEMPERATURE ENGINE TEMPERATURE SENSOR RETURN

1

995-BU

2

G833-PK

BOTTOM CAMSHAFT SPEED/TIMING- A BOTTOM CAMSHAFT SPEED/TIMING+ B

J100 P100

ENGINE INTAKE MANIFOLDAIR TEMPERATURE ENGINE TEMPERATURE SENSOR RETURN

1 2

C967-BU G833-PK

ENGINE TIMING CALIBRATION PROBE+ A ENGINE TIMING CALIBRATION PROBE- B J400 P400

J103 P103

(+) BATTERY

SIGNAL PLUS TO ECM SIGNAL MINUS TO ECM

TO ECM MOUNTING BOLT

ENGINE COOLANTTEMPERATURE ENGINE INTAKE MANIFOLDAIR TEMPERATURE

ENGINE TEMPERATURE SENSOR RETURN


ENGINE TIMING CALIBRATION PROBE+ ENGINE TIMING CALIBRATION PROBE-

56 57 65 66 69 20 21 G850-BU

G850-BU

ENGINE OILLEVEL SWITCH

INTAKEAIR HEATER RELAY

8

N/O RELAY

TO ENGINE CYLINDER HEAD (NOT CYLINDER HEAD GROUND STUD)

SENSOR / ACTUATOR SUPPLY

ECM GROUND STRAP

G856-WH G857-YL NOTEA

C987-RD

1 2

(-) BATTERY / SENSOR RETURN

INPUT #16

ENGINE OILPRESSURE SENSOR RETURN

BOTTOM CAMSHAFT SPEED/TIMINGBOTTOM CAMSHAFT SPEED/TIMING+

J501 P501

STARTING CIRCUIT

ENGINE OILPRESSURE SENSOR +5V

25 51 52 53 60

28 29 30 31 43 22 23

K995-OR

(+) BATTERY SWITCHED

ENGINE OILPRESSURE SENSOR

41

19 59 58

ENGINE INTAKE MANIFOLDAIR TEMPERATURE SENSOR

24 42


E965-BU E966-YL

J402 P402

BOTTOM CAMSHAFT ENGINE SPEED/TIMING SENSOR

ENGINEATMOSPHERIC PRESSURE ENGINE PRESSURE SENSOR RETURN

49 48 13 50

J401 P401

ENGINE COOLANT TEMPERATURE SENSOR

14 3 2 15 16 17

ENGINE BOOST PRESSURE ENGINE INJECTIONACTUATION PRESSURE

34 26 18 10 11 12

TOP CAMSHAFT ENGINE SPEED/TIMING SENSOR ENGINE OILLEVEL

ENGINE OILLEVEL SWITCH NOTEA

IAP CONTROLVALVE IAP CONTROLVALVE RETURN

33 32 35 9

995-BU C967-BU

C B A

61 62 70 40 27 6 7

INTAKEAIR HEATER

CONTROL PLUS FROM ECM CONTROL MINUS FROM ECM

P648 B A

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

DATA LINK PLUS DATA LINK MINUS

G850-BU C987-RD

NOTEA: THIS ISAN OPTIONALFEATURE NOT INSTALLED ONALL VEHICLES.

3126B & 3126E OEM VEHICLE ELECTRICAL SCHEMATIC 100AWITH 130APEAKAT 11V INTAKEAIR

B A

HEATER LAMP C987-RD

J648

CIRCUITS WITHIN THISAREAARE RECOMMENDATIONS CHECK ENGINE LAMP

N/O RELAY

R O 5 9 9 K

D R 7 8 9 C

ENGINE CONTROLMODULE L994-YL

WARNING LAMP 659-PK

KEY SWITCH

659-PK

FAST IDLE ENABLED LAMP

OFF ON START

K998-BU G880-PK

29 28 30 31 48 61

WARNING LAMP CHECK ENGINE LAMP OUTPUT #1 OUTPUT #9

E718-PK E991-GY G836-WH

10 12 13

OUTPUT #2 OUTPUT #3 OUTPUT #4

C981-GY

15 16

EXHAUST BRAKE ON/OFF SWITCH

L994-YL

OR

NOTEA

G880-PK

WAITTO START LAMP

EXHAUST BRAKE SOLENOID

FLYBACK

NOTEA

DIODE

EXHAUST BRAKE ON/OFF SWITCH NOTEA

ALTERNATOR GROUND

9 PIN CAB CONNECTOR TACHOMETER NOTEA

+BAT. B -BAT. A J H - 12V +

- 12V +

BAT TERY 3

BATTERY 2

C974-PU

SIGNAL+

SPEEDOMETER NOTEA

STARTER MOTOR (12V)

C973-GN SIGNAL-

B AT TERY 1

NOTEA

C973-GN

993-BR F713-OR 450-YL 451-BR

450-YL

SIGNAL+ SIGNAL-

451-BR NOTEA

J1587 - G E793-BU J1587 + F E794-YL A249-BK J1939 SHIELD E J1939 - D K990-GN J1939 + C K900-YL NOTEA

- 12V +

C974-PU

NOTEA

E793-BU E794-YL A249-BK K990-GN K900-YL

63 36 37 27 26 3 17 38 39 57 43 9 8 42 34 50 1

SPEEDOMETER POSITIVE SPEEDOMETER NEGATIVE

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

J1587 J1587 J1939 J1939 J1939

DATALINK NEGATIVE DATALINK POSITIVE DATALINK SHIELD DATALINK NEGATIVE DATALINK POSITIVE

14 J906-BR NOTEA

TOALLISON AT/MT/HT SHIFT MODULATOR FORAUTOMATIC TRANSMISSIONS

14AWG GXL 14AWG GXL 14AWG GXL 14AWG GXL

20A

ENGINE BLOCK

NOTEA

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

NOTEA NOTEA

H795-PK

C978-BR

C978-BR

C979-OR

C979-OR K999-GN K980-PK

SET/RESUME SWITCH

FAST IDLE ENABLE SWITCH

NOTEA

H795-PK

NOTEA

H795-PK

L902-GN

C975-WH

CRUISE CONTROLON/OFF SWITCH

C992-PU

C992-PU SERVICE BRAKE PEDALPOSITION SWITCH #2 N/O +BAT. G882-WH

(PEDALRELEAS ED POSITION) NOTEA

CLUTCH PEDALPOSITION SWITCH N/C

R E 8 N P a R g e 1 , C 3 o l 6 o r 8 2 0 5

H795-PK (PEDALRELEASED POSITION)

DIAGNOSTIC ENABLE SWITCH H795-PK

G879-OR

G844-PK

N/O MOMENTARY SWITCH

+BAT.

TRANSMISSION NEUTRALSWITCH N/O 409-OR

A/C HIGH PRESSURE SWITCH N/C

(TRANSMISSION IN GEAR) NOTEA

E971-GN

H795-PK

COMPONENTS WITHIN THISAREAARE CATERPILLAR PROVIDED

SENSORACCELERATOR PEDALPOSITION

G844-PK C983-WH C984-YL 409-OR E971-GN

PASSIVE MAGNETIC VEHICLE SPEED SENSOR

ACCELERATOR PEDAL SENSOR/SWITCH SENSOR RETURN +8 V ACCELERATOR PEDAL POSITION

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

C977-BU

NOTEA

NOTEA

L902-GN G840-PU C975-WH K982-YL G841-GN

SERVICE BRAKE PEDALPOSITION SWITCH N/C


NOTEA


BK RD WH

B A C

G808-BU G809-GN

1 2

H795-PK C985-BU C986-BR

J403 P403

COOLING FAN SOLENOID NOTEA

FLYBACK DIODE

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

70 25 52 53 65 67 19 20 51 35

IGNITION KEY SWITCH UNSWITCHED +BATTERY UNSWITCHED +BATTERY -BATTERY -BATTERY OUTPUT #6 OUTPUT #7 SET

44 56 58 40 21

RESUME INPUT #1 (PTO ON/OFF SWITCH) INPUT #2 INPUT #18 OUTPUT #8

59

CRUISE CONTROLON/OFF SWITCH INPUT #3 INPUT #4 SERVICE BRAKE PEDALPOSITION SWITCH

60 7 45 55 47 64 6

INPUT #5 INPUT #13 INPUT #6

18 22 23

INPUT SENSOR RETURN #1 CLUTCH PEDALPOSITION SWITCH

2 46

+5V INPUT #7 ENGINE COOLANT LEVELNORMAL ENGINE COOLANT LEVELLOW INPUT #12

49 54 62 24 41 69

INPUT #11

32 33

VEHICLE SPEED IN POSITIVE VEHICLE SPEED IN NEGATIVE

68 5

INPUT #8 (REMOTEACCELERATOR) AP SENSOR/SWITCH SENSOR RETURN

4

+8V

66 11

ACCELERATOR PEDAL POSITION OUTPUT #5

P1 J1 VEHICLE HARNESS CONNECTOR


TOP VIEW INLET AIR TEMPERATURE SENSOR

INJECTION ACTUATION PRESSURE SENSOR

ATMOSPHERIC PRESSURE SENSOR

INLET AIR HEATER

BOOST PRESSURE SENSOR


ENGINE GROUND STUD CONNECTION

INJECTION ACTUATION PRESSURE CONTROL VALVE

INLET AIR HEATER RELAY

INLET AIR HEATER INJECTION ACTUATION PRESSURE SENSOR

INLET AIR TEMPERATURE SENSOR

ATMOSPHERIC PRESSURE SENSOR (SELECT RATINGS ONLY)


ENGINE HARNESS CONNECTOR J2/P2

INJECTOR HARNESS GROMMET ENGINE GROUND STUD CONNECTION

FormNumber

Troubleshooting

Intake Air Heater Lamp

Intake Air Heater

17

0070-05 0070-06

AT/MT/HT Transmission Relay

SocketContact

38

Cylinder#1Injectorcurrentfault Cylinder#2Injectorcurrentfault

Intake Manifold Air Temperature Sensor PinContact

Flash Codes

0001-11 0002-11

30

(Specific Ratings Only)

Plug Wedge

No Detected Faults

RPMX 1000

PlugWedge

Receptacle Wedge

D es cr ip ti on

00-00

3126B & 3126E ENGINE ELECTRICAL SCHEMATIC


L983-WH

12 11

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

J302 P302

B A

J303 P303

J304 P304

J305 P305

J306 P306

B A

B A

B A

B A

B A

ENGINE HARNESS CONNECTOR ENGINE CONTROLMODULE

10 9 8 7

L984-OR

A706-GY

P2 J2

6 5 4 3 2 1

INJECTOR

INJECTOR

INJECTOR

INJECTOR

INJECTOR

CYLINDER NO.1

CYLINDER NO.2

CYLINDER NO.3

CYLINDER NO.4

CYLINDER NO.5

INJECTOR

L983-WH L984-OR

44 45

INJECTOR RETURN CYLINDERS 1 & 2 INJECTOR RETURN CYLINDERS 3 & 4

L985-YL A706-GY A705-BU A704-GN A703-BR A702-PU A701-GY

46 55 54 39 38 37 36 47 67

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

P300 J300

CYLINDER NO.6

68

A705-BU

1 63 64 4 5

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

INJECTIONACTUATION PRESSURE CONTROLVALVE (IAPCV) ENGINE BOOST PRESSURE ENGINE BOOST PRESSURE

C B A


SENSOR

G854-PK G855-PU

J500 P500

A746-PK G829-GN G828-WH

A746-PK G849-BR

C200

A747-GY G829-GN G828-WH

ENGINE INJECTION ACTUATION PRESSURE SENSOR

ENGINE INJECTIONACTUATION PRESSURE

C B A


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

C204

ENGINEATMOSPHERIC PRESSURE SENSOR NOTEA

ENGINEATMOSPHERIC PRESSURE

C

A747-GY

ENGINE PRESSURE SENSOR RETURN

B A

G829-GN G828-WH


C203

ENGINE OIL PRESSURE SENSOR NOTEA

ENGINE OILPRESSURE SENSOR ENGINE OILPRESSURE SENSOR RETURN ENGINE OILPRESSURE SENSOR +5V

G883-GN G458-GY 994-GY G827-BU G826-BR

C201

G833-PK

ENGINEOILLEVELRETURN

1

G458-GY G829-GN

2


J802 P802

A B

E963-BK E964-WH

ENGINE COOLANTTEMPERATURE ENGINE TEMPERATURE SENSOR RETURN

1

995-BU

2

G833-PK

BOTTOM CAMSHAFT SPEED/TIMING- A BOTTOM CAMSHAFT SPEED/TIMING+ B

J100 P100

ENGINE INTAKE MANIFOLDAIR TEMPERATURE ENGINE TEMPERATURE SENSOR RETURN

1 2

C967-BU G833-PK

ENGINE TIMING CALIBRATION PROBE+ A ENGINE TIMING CALIBRATION PROBE- B J400 P400

J103 P103

(+) BATTERY

SIGNAL PLUS TO ECM SIGNAL MINUS TO ECM

TO ECM MOUNTING BOLT

ENGINE COOLANTTEMPERATURE ENGINE INTAKE MANIFOLDAIR TEMPERATURE

ENGINE TEMPERATURE SENSOR RETURN


ENGINE TIMING CALIBRATION PROBE+ ENGINE TIMING CALIBRATION PROBE-

56 57 65 66 69 20 21 G850-BU

G850-BU

ENGINE OILLEVEL SWITCH

INTAKEAIR HEATER RELAY

8

N/O RELAY

TO ENGINE CYLINDER HEAD (NOT CYLINDER HEAD GROUND STUD)

SENSOR / ACTUATOR SUPPLY

ECM GROUND STRAP

G856-WH G857-YL NOTEA

C987-RD

1 2

(-) BATTERY / SENSOR RETURN

INPUT #16

ENGINE OILPRESSURE SENSOR RETURN

BOTTOM CAMSHAFT SPEED/TIMINGBOTTOM CAMSHAFT SPEED/TIMING+

J501 P501

STARTING CIRCUIT

ENGINE OILPRESSURE SENSOR +5V

25 51 52 53 60

28 29 30 31 43 22 23

K995-OR

(+) BATTERY SWITCHED

ENGINE OILPRESSURE SENSOR

41

19 59 58

ENGINE INTAKE MANIFOLDAIR TEMPERATURE SENSOR

24 42


E965-BU E966-YL

J402 P402

BOTTOM CAMSHAFT ENGINE SPEED/TIMING SENSOR

ENGINEATMOSPHERIC PRESSURE ENGINE PRESSURE SENSOR RETURN

49 48 13 50

J401 P401

ENGINE COOLANT TEMPERATURE SENSOR

14 3 2 15 16 17

ENGINE BOOST PRESSURE ENGINE INJECTIONACTUATION PRESSURE

34 26 18 10 11 12

TOP CAMSHAFT ENGINE SPEED/TIMING SENSOR ENGINE OILLEVEL

ENGINE OILLEVEL SWITCH NOTEA

IAP CONTROLVALVE IAP CONTROLVALVE RETURN

33 32 35 9

995-BU C967-BU

C B A

61 62 70 40 27 6 7

INTAKEAIR HEATER

CONTROL PLUS FROM ECM CONTROL MINUS FROM ECM

P648 B A

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

DATA LINK PLUS DATA LINK MINUS

G850-BU C987-RD


3126B & 3126E OEM VEHICLE ELECTRICAL SCHEMATIC 100AWITH 130APEAKAT 11V INTAKEAIR

B A

HEATER LAMP C987-RD

J648

CIRCUITS WITHIN THISAREAARE RECOMMENDATIONS CHECK ENGINE LAMP

N/O RELAY

R O 5

D R 7 8 9 C

9 9 K

ENGINE CONTROLMODULE L994-YL

WARNING LAMP 659-PK

KEY SWITCH

659-PK L994-YL

FAST IDLE ENABLED LAMP

OFF ON

OR

START

K998-BU G880-PK

NOTEA

G880-PK

WAITTO START LAMP

EXHAUST BRAKE SOLENOID

FLYBACK

NOTEA

DIODE

E718-PK E991-GY G836-WH


C981-GY NOTEA

STARTER MOTOR (12V)

GROUND

- 12V +

- 12V +

BAT TERY 3

BATTERY 2

9 PIN CAB CONNECTOR TACHOMETER NOTEA

SIGNAL-

450-YL

SIGNAL+ SIGNAL-

451-BR

B AT TERY 1

NOTEA

17 38 39

E793-BU E794-YL A249-BK K990-GN K900-YL

57 43 9 8 42 34 50 1 14

J906-BR NOTEA

TOALLISON AT/MT/HT SHIFT MODULATOR FORAUTOMATIC TRANSMISSIONS

14AWG GXL 14AWG GXL 14AWG GXL 14AWG GXL

20A

ENGINE BLOCK

NOTEA

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

NOTEA NOTEA

C978-BR C979-OR

H795-PK

SET/RESUME SWITCH

H795-PK

NOTEA

H795-PK

C978-BR C979-OR K999-GN

FAST IDLE ENABLE SWITCH

NOTEA

L902-GN

C975-WH

CRUISE CONTROLON/OFF SWITCH

C992-PU SERVICE BRAKE PEDALPOSITION SWITCH #2 N/O +BAT. G882-WH


(PEDALRELEAS ED POSITION) NOTEA

DIAGNOSTIC ENABLE SWITCH H795-PK

G879-OR

G844-PK


+BAT.

TRANSMISSION NEUTRALSWITCH N/O 409-OR

A/C HIGH PRESSURE SWITCH N/C

(TRANSMISSION IN GEAR) NOTEA

E971-GN

H795-PK

COMPONENTS WITHIN THISAREAARE CATERPILLAR PROVIDED

ACCELERATOR PEDAL POSITION

G844-PK C983-WH C984-YL 409-OR E971-GN

PASSIVE MAGNETIC VEHICLE SPEED SENSOR

ACCELERATOR PEDAL SENSOR/SWITCH SENSOR RETURN +8 V

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

C977-BU

NOTEA

NOTEA

L902-GN G840-PU

C992-PU

CLUTCH PEDALPOSITION SWITCH N/C NOTEA

K980-PK

C975-WH K982-YL G841-GN

SERVICE BRAKE PEDALPOSITION SWITCH N/C


R E 8 N P a R g e 1 , C 3 o l 6 o r 8 2 0 5


BK RD WH

SENSORACCELERATOR PEDALPOSITION

B A C

G808-BU G809-GN

1 2

H795-PK C985-BU C986-BR

J403 P403

COOLING FAN SOLENOID NOTEA

FLYBACK DIODE


993-BR

NOTEA

E793-BU E794-YL A249-BK J1939 SHIELD E J1939 - D K990-GN J1939 + C K900-YL NOTEA

- 12V +

OUTPUT #2 OUTPUT #3 OUTPUT #4

15 16

F713-OR 450-YL 451-BR

NOTEA

C973-GN

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

WARNING LAMP CHECK ENGINE LAMP OUTPUT #1 OUTPUT #9

13

63 36 37 27 26 3

C974-PU C973-GN

NOTEA

+BAT. B -BAT. A J H J1587 - G J1587 + F

C974-PU

SIGNAL+

SPEEDOMETER ALTERNATOR

29 28 30 31 48 61 10 12

70 25 52 53 65 67

SPEEDOMETER POSITIVE SPEEDOMETER NEGATIVE

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

J1587 J1587 J1939 J1939 J1939

DATALINK NEGATIVE DATALINK POSITIVE DATALINK SHIELD DATALINK NEGATIVE DATALINK POSITIVE

IGNITION KEY SWITCH UNSWITCHED +BATTERY UNSWITCHED +BATTERY -BATTERY -BATTERY

19 20 51 35 44 56 58 40 21

OUTPUT #6 OUTPUT #7

59 60 7 45

CRUISE CONTROLON/OFF SWITCH INPUT #3 INPUT #4 SERVICE BRAKE PEDALPOSITION SWITCH

55 47 64 6

INPUT #5 INPUT #13 INPUT #6

18 22 23 2 46 49 54 62 24 41 69

SET RESUME INPUT #1 (PTO ON/OFF SWITCH) INPUT #2 INPUT #18 OUTPUT #8

INPUT SENSOR RETURN #1 CLUTCH PEDALPOSITION SWITCH +5V INPUT #7 ENGINE COOLANT LEVELNORMAL ENGINE COOLANT LEVELLOW INPUT #12 INPUT #11

32 33

VEHICLE SPEED IN POSITIVE VEHICLE SPEED IN NEGATIVE

68 5

INPUT #8 (REMOTEACCELERATOR) AP SENSOR/SWITCH SENSOR RETURN

4

+8V

66 11

ACCELERATOR PEDAL POSITION OUTPUT #5

P1 J1 VEHICLE HARNESS CONNECTOR


TOP VIEW INLET AIR TEMPERATURE SENSOR

INJECTION ACTUATION PRESSURE SENSOR

ATMOSPHERIC PRESSURE SENSOR

INLET AIR HEATER



ENGINE GROUND STUD CONNECTION

INJECTION ACTUATION PRESSURE CONTROL VALVE

INLET AIR HEATER RELAY

INLET AIR HEATER INJECTION ACTUATION PRESSURE SENSOR

INLET AIR TEMPERATURE SENSOR

ATMOSPHERIC PRESSURE SENSOR (SELECT RATINGS ONLY)


ENGINE HARNESS CONNECTOR J2/P2

INJECTOR HARNESS GROMMET ENGINE GROUND STUD CONNECTION

VEHICLE HARNESS CONNECTOR J1/P1

INJECTION ACTUATION PRESSURE CONTROL VALVE (IAPCV)

ENGINE SPEED/TIMING SENSORS

COOLANT TEMPERATURE SENSOR

OIL PRESSURE SENSOR (OPTIONAL)

OIL LEVEL SWITCH (OPTIONAL) ENGINE CONTROL MODULE

LEFT SIDE VIEW

Caterpillar 3126 Plano

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