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PCM Harness Resistance

Turn ignition switch to LOCK position. Disconnect PCM and appropriate component harness connectors. Check for open or short circuits between appropriate PCM harness connector terminal and appropriate component harness connector terminal. See POWERTRAIN CONTROL MODULE (PCM)  table. See WIRING DIAGRAMS. If harness is open or shorted, repair as necessary.

Fig 1: Identifying Powertrain Control Module (PCM) Harness Connector Terminals
G98H00866Courtesy of GENERAL MOTORS CORP.
POWERTRAIN CONTROL MODULE (PCM) HARNESS CONNECTOR COLOR IDENTIFICATION

Connector Color
C1 Blue
C2 Red
C3 Natural
C4 Black
POWERTRAIN CONTROL MODULE (PCM) (1)

Connector (2) Terminal Wire Color Function
C1 1 & 2 ***** Not Used
C1 3 BRN/WHT CMP 1x Signal
C1 4-6 ***** Not Used
C1 7 TAN HO2S Bank 2 Sensor 1 Low
C1 8 PNK/BLK CMP Low
C1 9 PPL Fuel Gauge
C1 10-13 ***** Not Used
C1 14 BRN Air Relay Control (CA Only)
C1 15 YEL/BLK VSS Signal
C1 16 & 17 ***** Not Used
C1 18 PPL/WHT Dual Tank Fuel Module
C1 19 PPL/WHT HO2S Bank 1 Sensor 1 Signal
C1 20 PPL HO2S Bank 1 Sensor 2 Signal
C1 21 PPL HO2S Bank 2 Sensor 1 Signal
C1 22 PPL/WHT HO2S Bank 2 Sensor 3 Signal
C1 23 ***** Not Used
C1 24 TAN HO2S Bank 1 Sensor 2 Ground
C1 25 TAN/WHT HO2S Bank 1 Sensor 1 Ground
C1 26 TAN/WHT HO2S Bank 1 Sensor 2 Ground
C1 27 ***** Not Used
C1 28 PPL CKP Sensor Ground
C1 29 LT GRN/BLK VSS Ground
C1 30 PPL/WHT VSS Signal
C1 31 YEL CKP 4x Sensor Signal
C1 32 ***** Not Used
C2 1 ***** Not Used
C2 2 WHT EVAP Canister Vent Solenoid Control
C2 3 ***** Not Used
C2 4 YEL/BLK 2-3 Shift Solenoid Control
C2 5 ***** Not Used
C2 6 LT GRN 1-2 Shift Solenoid Control
C2 7 BRN TCC PWM Solenoid Control
C2 8 BLK Fuel Injector No. 1 Control
C2 9 DK BLU/WHT Fuel Injector No. 8 Control
C2 10 BRN EGR Pintle Position Signal
C2 11 LT GRN/BLK Fuel Injector No. 2 Control
C2 12 RED/BLK Fuel Injector No. 7 Control
C2 13 LT GRN/WHT IAC Coil B High
C2 14 LT BLU/WHT IAC Coil A High
C2 15 BLK/WHT Fuel Injector No. 5 Control
C2 16 YEL/BLK Fuel Injector No. 6 Control
C2 17 & 18 ***** Not Used
C2 19 DK BLU KS Signal
C2 20 ***** Not Used
C2 21 LT GRN MAP Sensor Signal
C2 22 TAN IAT Sensor Signal
C2 23 YEL ECT Sensor Signal
C2 24 DK BLU TP Sensor Signal
C2 25 DK GRN Fuel Tank Pressure Sensor Signal
C2 26 ***** Not Used
C2 27 YEL/BLK TFT Sensor Signal
C2 28 YEL MAF Sensor Signal
C2 29 LT GRN/BLK IAC Coil High
C2 30 LT BLU/BLK IAC Coil Low
C2 31 LT BLU/BLK Fuel Injector No. 4 Control
C2 32 PNK/BLK Fuel Injector No. 3 Control
C3 1 DK GRN/WHT A/C Compressor Enable Relay Control
C3 2 DK GRN/WHT EVAP Canister Purge Solenoid Control
C3 3 ***** Not Used
C3 4 BLK ECT/TP Sensor Ground
C3 5 ***** Not Used
C3 6 RED/BLK PC Solenoid High
C3 7 DK BLU/WHT Input Shaft Speed Sensor Low
C3 8 RED/BLK Input Shaft Speed Sensor High
C3 9 WHT IC Control
C3 10 ***** Not Used
C3 11 RED Transmission Range C Signal
C3 12 GRY TP Sensor Reference Voltage
C3 13 PPL/WHT Fuel Level Module (Single Tank)
C3 14 DK BLU A/C Recirculation
C3 15 ***** Not Used
C3 16 LT BLU/WHT PC Solenoid Low
C3 17 BLK/WHT PCM Ground
C3 18 BLK/WHT PCM Ground
C3 19 BLK Sensor Ground (IAT/MAP/EGR)
C3 20 ***** Not Used
C3 21 ORG Battery Voltage
C3 22 DK BLU Transmission Range B Signal
C3 23 PNK Transmission Range A Signal
C3 24 ***** Not Used
C3 25 DK GRN/WHT A/C Request Signal
C3 26 ***** Not Used
C3 27 GRY Reference Voltage (EGR/MAP)
C3 28 & 29 ***** Not Used
C3 30 DK GRN A/C Pressure Signal
C3 31 & 32 ***** Not Used
C4 1 DK GRN/WHT Fuel Pump Relay Control
C4 2 ***** Not Used
C4 3 DK GRN/WHT VSS Output Signal (TCC/Radio/Cruise Control)
C4 4 DK GRN VSS Output Signal (Speedometer)
C4 5 BRN/WHT MIL Control
C4 6 ***** Not Used
C4 7 DK GRN Inlet Air Actuator
C4 8 ***** Not Used
C4 9 DK BLU Auxiliary Cooling Fan
C4 10 PPL Brake Signal
C4 11 PPL Serial Data (Class II)
C4 12 BLK Dual Fuel Module Return
C4 13 BRN Ignition Voltage
C4 14 & 15 ***** Not Used
C4 16 RED EGR Valve Control
C4 17 ***** Not Used
C4 18 PNK Ignition Voltage
C4 19 BLK/WHT 4WD Engaged Signal
C4 20 WHT EGR Valve Control
C4 21 & 22 ***** Not Used
C4 23 GRY/BLK Transfer Case High Low Switch
C4 24 LT BLU/BLK Cruise Engaged Signal
(1) See Fig 1.
(2) For connector color identification, see POWERTRAIN CONTROL MODULE (PCM) HARNESS CONNECTOR COLOR IDENTIFICATION  table.
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