Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1998SUBURBAN K2500, 7.4 J, PART TIMEREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - SYSTEM & COMPONENT TESTING 7.4LCOMPUTERIZED ENGINE CONTROLSCONTROL UNITPCM HARNESS RESISTANCE
1998 Chevrolet Suburban K2500, 7.4 J, Part Time
PCM Harness Resistance
1998 Chevrolet Suburban K2500, 7.4 J, Part TimeSECTION 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.
POWERTRAIN CONTROL MODULE (PCM) (1)
| Connector | 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 | ||
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.