PCM Connector End View C4

Courtesy of GENERAL MOTORS CORP.
Connector Part Information		31-Pin WHT
Pin	Wire Color	Function
1	BLK	Ignition Positive Voltage
2	-	Not Used
3	RED/WHT	Battery Voltage
4	RED	EVAP Pressure Switching Solenoid Control
5	BLK	Engine Speed Output for Tachometer
6	GRN	Fan 1 Relay Control
7	GRN/BLK	Fan 2 Relay Control
8-9	-	Not Used
10	GRN/RED	Circuit Opening Relay Control
11	RED/YEL	MIL Control
12	GRN	Electrical Load Idle-Up Signal, Tail Lamps
13	WHT	Electrical Load Idle-Up Signal, Rear Defogger
14	YEL	Supplemental Inflatable Restraint (SIR) System Signal
15	-	Not Used
16	BLU/WHT	Cruise Control Idle
17	-	Not Used
18	BLU/RED	Serial Data
19	PNK	Data Link Connector (DLC)
20	PNK/BLK	Diagnostic Request Circuit
21	BLU	Fuel Tank Pressure (FTP) Sensor Input
22-31	-	Not Used
*Automatic Transmission Only

Courtesy of GENERAL MOTORS CORP.
Connector Part Information		31-Pin WHT
Pin	Wire Color	Function
1	BLK	Ignition Positive Voltage
2	-	Not Used
3	RED/WHT	Battery Voltage
4	RED	EVAP Pressure Switching Solenoid Control
5	BLK	Engine Speed Output for Tachometer
6	GRN	Fan 1 Relay Control
7	GRN/BLK	Fan 2 Relay Control
8	BLK/WHT	EFI Relay Control High
9	BLK/ORN	Ignition Positive Voltage
10	GRN/RED	Circuit Opening Relay Control
11	RED/YEL	MIL Control
12	GRN	Electrical Load Idle-Up Signal, Tail Lamps
13	WHT	Electrical Load Idle-Up Signal, Rear Defogger
14	YEL	Supplemental Inflatable Restraint (SIR) System Signal
15	-	Not Used
16	BLU/WHT	Cruise Control Idle
17	-	Not Used
18	BLU/RED	Serial Data
19	PNK	Data Link Connector (DLC)
20	PNK/BLK	Diagnostic Request Circuit
21	BLU	Fuel Tank Pressure (FTP) Sensor Input
22-31	-	Not Used