GM Service Manual Online
For 1990-2009 cars only
Connector 1: Back View of PCM Connector - C1
Connector 2: Back View of PCM Connector - C2
Connector 3: Back View of PCM Connector - C3
Connector 4: Back View of PCM Connector - C4

Back View of PCM Connector - C1


Object Number: 789637  Size: CF

Connector Part Information

  • OEM: N/A
  • Service: N/A
  • Description: 34-Pin (WH)

Back View of PCM Connector - C1

Pin

Wire Color

Function

1

YE

Fuel Injector 1 Control

2

BK

Fuel Injector 2 Control

3

WH

Fuel Injector 3 Control

4

BU

Fuel Injector 4 Control

5

BN

Ground

6

WH/BK

Ground

7

WH/BK

Ground

8

RD/BU

Ignition Trigger Signal Coil 1

9

YE/GN

Ignition Trigger Signal Coil 2

10

GY

Ignition Trigger Signal Coil 3

11

WH

Ignition Trigger Signal Coil 4

12

BK/YE

Camshaft Position (CMP) Actuator Solenoid Valve Low Control

13

YE

Camshaft Position (CMP) Actuator Solenoid Valve High Control

14

L-GN/BK

Fan 2 Relay Control

15

--

Not Used

16

RD

Ignition Positive Voltage*

17

BK

Crank Signal*

18

YE

5-Volt Reference Circuit

19

WH

Engine Coolant Temperature (ECT) Sensor Input

20

YE/BK

Intake Air Temperature (IAT) Sensor Input

21

L-GN

Throttle Position (TP) Sensor 1 Input

22-23

--

Not Used

24

BU/YE

Ignition Fail Safe Input

25-26

--

Not Used

27

RD

EVAP Canister Vent Solenoid Valve Control

28

BN

Sensor Ground

29

BU/WH

Mass Air Flow (MAF) Sensor Signal Low

30

GN

Mass Air Flow (MAF) Sensor Signal High

31

L-GN

Throttle Position (TP) Sensor 2 Input

32-33

--

Not Used

34

BU/BK

EVAP Canister Purge Solenoid Valve Control

*Automatic Transmission Only

Back View of PCM Connector - C2


Object Number: 789639  Size: CF

Connector Part Information

  • OEM: N/A
  • Service: N/A
  • Description: 35-Pin (WH)

Back View of PCM Connector - C2

Pin

Wire Color

Function

1

BK

Knock Sensor (KS) Signal High

2

WH/BK

Ground

3

WH

TAC Motor Control Low

4

L-GN

TAC Motor Control High

5

PK

Heated Oxygen Sensor (HO2S) 1 Heater Circuit Control

6

WH/BK

Ground

7

WH/BK

Heated Oxygen Sensor (HO2S) Shield Ground

8

BU/RD

Power Steering Pressure (PSP) Switch Input

9

BU

Shift Solenoid (SS) 2 Control*

10

BU/WH

Torque Converter Clutch (TCC) Control*

11

RD/YE

Shift Solenoid (SS) 1 Control*

12

PK

or

BK

Line Pressure Control (PC) Solenoid Control Low w/AT

or

Crank Signal w/MT

13

RD/WH

Line Pressure Control (PC) Solenoid Control High*

14-15

--

Not Used

16

L-GN

Fan 1 Relay Control

17

GY

TAC Shield Ground

18-20

--

Not Used

21

PK/BK

Heated Oxygen Sensor (HO2S) 2 Heater Circuit Control

22

--

Not Used

23

BK

Heated Oxygen Sensor (HO2S) 1 Input

24

BK

Camshaft Position (CMP) Sensor Input

25

BK

Crankshaft Position (CKP) Sensor Input

26-27

--

Not Used

28

WH

Knock Sensor (KS) Signal Low

29

WH

Heated Oxygen Sensor (HO2S) 2 Input

30

--

Not Used

31

WH

Heated Oxygen Sensor (HO2S) 1 Low Reference

32

--

Not Used

33

WH

CMP Sensor and CKP Sensor Ground

34

--

Not Used

35

WH/BK

Ground

*Automatic Transmission Only

Back View of PCM Connector - C3


Object Number: 789640  Size: CF

Connector Part Information

  • OEM: N/A
  • Service: N/A
  • Description: 35-Pin (WH)

Back View of PCM Connector - C3

Pin

Wire Color

Function

1

YE

AC Pressure Switch

2

YE/BK

AC Compressor Clutch Relay Control

3-5

--

Not Used

6

BK/RD

Throttle Actuator Control (TAC) System Ignition Voltage

7

L-GN

Overdrive (OD) Indicator Control*

8

L-GN/BK

Park Neutral Position (PNP) Switch L Position Signal*

9

L-GN

Park Neutral Position (PNP) Switch 2 Position Signal*

10

BU

Park Neutral Position (PNP) Switch D Position Signal*

11

RD/BK

Park Neutral Position (PNP) Switch R Position Signal*

12

GN/OG

Cruise Control Interrupt Circuit

13

GN/RD

Cruise Control Indicator Lamp

14

YE/RD

Engine Coolant Temperature Gage Output

15-16

--

Not Used

17

PU/WH

Vehicle Speed Sensor (VSS) Input

18

--

Not Used

19

GN/WH

Cruise Brake Switch Signal

20-23

--

Not Used

24

GN/YE

Cruise Control Switch

25-27

--

Not Used

28

YE

AC Request Signal

29

GN/BK

Overdrive (OD) Switch Signal*

30-31

--

Not Used

32

BK/BU

Evaporator Temperature Sensor Input

33

GN/WH

AC On Signal

34-35

--

Not Used

*Automatic Transmission Only

Back View of PCM Connector - C4


Object Number: 789641  Size: CF

Connector Part Information

  • OEM: N/A
  • Service: N/A
  • Description: 31-Pin (WH)

Back View of PCM Connector - C4

Pin

Wire Color

Function

1

BK

Ignition Positive Voltage

2

--

Not Used

3

RD/WH

Battery Voltage

4

GY

EVAP Vacuum Leak Pump Control

5

BK

Engine Speed Output for Tachometer

6-7

--

Not Used

8

BK/WH

EFI Relay High Control

9

BK/OG

Ignition Positive Voltage

10

GN/RD

Circuit Opening Relay Control

11

RD/YE

MIL Control

12

GN

Electrical Load Idle-Up Signal, Tail Lamps

13

WH

Electrical Load Idle-Up Signal, Rear Defogger

14

YE

Supplemental Inflatable Restraint (SIR) System Signal

15-16

--

Not Used

17

RD/YE

Engine Speed Output to Brake Pressure Modulator Valve (BPMV), with Traction Control Only

18

BU/RD

Serial Data

19

PK

Brake Pressure Modulator Valve (BPMV) Serial Data

20

PK/BK

Diagnostic Request Circuit

21

BU

Fuel Tank Pressure (FTP) Sensor Input

22

GN

Accelerator Pedal Position (APP) Sensor 1 Signal

23

WH

Accelerator Pedal Position (APP) Sensor 2 Signal

24

BK/WH

EFI Signal High, with Traction Control Only

25

RD/WH

Traction Control High, with Traction Control Only

26

BK

Accelerator Pedal Position (APP) Sensor 1 Reference Voltage

27

BK

Accelerator Pedal Position (APP) Sensor 2 Reference Voltage

28

YE

Accelerator Pedal Position (APP) Sensor 1 Low Reference

29

YE

Accelerator Pedal Position (APP) Sensor 2 Low Reference

30

BU

EFI Signal Low, with Traction Control Only

31

WH

Traction Control Low, with Traction Control Only

*Automatic Transmission Only