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

Back View of PCM Connector C1


Object Number: 789637  Size: CF

Connector Part Information

    • 34-Pin
    • WH

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

Crank Signal

13

BK/YE

Camshaft Position (CMP) Actuator Solenoid Valve Low Control

14

YE

Camshaft Position (CMP) Actuator Solenoid Valve High Control

15

BU/WH

Auxiliary Intake Air Control Solenoid Control

16

BK/BU

Idle Air Control (IAC) Valve Control

17

--

Not Used

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 Input

22-23

--

Not Used

24

BU/YE

Ignition Fail Safe Input

25

RD

EVAP Canister Vent Solenoid Valve Control

26

BK

Camshaft Position (CMP) Sensor Input

27

BK

Crankshaft Position (CKP) Sensor Input

28

BN

Sensor Ground

29

BU/WH

Mass Air Flow (MAF) Sensor Signal Low

30

GN

Mass Air Flow (MAF) Sensor Signal High

31-33

--

Not Used

34

WH

CMP Sensor and CKP Sensor Ground

Back View of PCM Connector C2


Object Number: 789639  Size: CF

Connector Part Information

    • 35-Pin
    • WH

Pin

Wire Color

Function

1

BK

Knock Sensor (KS) Signal High

2

WH

Knock Sensor (KS) Signal Low

3-5

--

Not Used

6

PK

Heated Oxygen Sensor (HO2S) 1 Heater Circuit Control

7

WH/BK

Ground

8

GY

EVAP Vacuum Leak Pump Control

9

L-GN/BK

Fan 2 Relay Control

10-15

--

Not Used

16

BU/YE

Rocker Arm Oil Control Solenoid Valve Low Control

17

BK

Rocker Arm Oil Control Solenoid Valve High Control

18

--

Not Used

19

BU/BK

EVAP Canister Purge Solenoid Valve Control

20

--

Not Used

21

L-GN

Fan 1 Relay Control

22

RD

Heated Oxygen Sensor (HO2S) 1 Input

23-26

--

Not Used

27

YE

AC Pressure Switch

28

WH/BK

Ground

29

--

Not Used

30

BU/RD

Power Steering Pressure (PSP) Switch Input

31-35

--

Not Used

Back View of PCM Connector C3


Object Number: 789640  Size: CF

Connector Part Information

    • 35-Pin
    • WH

Pin

Wire Color

Function

1-2

--

Not Used

3

BK

Engine Speed Output

4

BK/WH

EFI Relay High Control

5

YE/BK

AC Compressor Clutch Relay Control

6-7

--

Not Used

8

BU/WH

Crusie Control Idle

9-13

--

Not Used

14

YE/RD

Engine Coolant Temperature Gage Output

15

BU/RD

Serial Data

16

GN/RD

Circuit Opening Relay Control

17

PU/WH

Vehicle Speed Sensor (VSS) Input

18

--

Not Used

19

GN/WH

Brake Switch Signal

20-22

--

Not Used

23

WH

Heated Oxygen Sensor (HO2S) 2 Input

24-30

--

Not Used

31

BK/WH

Rocker Arm Oil Pressure Switch Input

32

BK/BU

Evaporator Temperature Sensor Input

33

GN/WH

AC On Signal

34

GN

Secondary AIR Pressure Sensor Input

35

--

Not Used

Back View of PCM Connector C4


Object Number: 789641  Size: CF

Connector Part Information

    • 31-Pin
    • WH

Pin

Wire Color

Function

1

BK

Ignition Positive Voltage

2

--

Not Used

3

RD/WH

Battery Voltage

4

BK/BU

Secondary AIR Solenoid Valve Control

5

BK/OG

Secondary AIR Pump Relay Control

6

--

Not Used

7

PK/BK

Heated Oxygen Sensor (HO2S) 2 Heater Circuit Control

8

--

Not Used

9

BK/OG

Ignition Positive Voltage

10

YE

AC Request Signal

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

15-18

--

Not Used

19

PK

Data Link Connector (DLC)

20

PK/BK

Diagnostic Request Circuit

21

BU

Fuel Tank Pressure (FTP) Sensor Input

22-31

--

Not Used