1998 Cadillac Eldorado BaseFACTORY OEM SERVICE PROCEDURE

PCM Harness Resistance

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

Fig 1: Identifying Powertrain Control Module (PCM) Harness Connector Terminals
G98F00864Courtesy of GENERAL MOTORS CORP.
POWERTRAIN CONTROL MODULE (PCM) CONNECTOR I.D. (1)

Connector Function Wire Color Terminal
C1 1-4 ***** Not Used
C1 5 DK BLU/WHT Input Shaft Speed Sensor Low
C1 6 RED/WHT Input Shaft Speed Sensor High
C1 7 BLK Sensor Ground
C1 8 LT GRN/BLK Idle Air Control
C1 9 LT BLU/BLK Idle Air Control
C1 10 LT BLU/WHT Idle Air Control
C1 11 LT GRN/WHT Idle Air Control
C1 12 BLK Throttle Position Sensor Signal
C1 13 YEL Transmission Fluid Temperature Sensor
C1 14 & 15 ***** Not Used
C1 16 GRY Fuel Pump Feedback
C1 17 BLK Engine Coolant Temperature Sensor Signal
C1 18 LT GRN Powertrain Control Module Ignition Voltage
C1 19 PNK Powertrain Control Module Ignition Voltage
C1 20 ORG Powertrain Control Module Battery Voltage
C1 21 BLK/WHT Powertrain Control Module Ground
C1 22 TAN/BLK Torque Converter Clutch Solenoid Control
C1 23 LT GRN Shift Solenoid A Control
C1 24 PPL Lift/Drive Signal Output
C1 25 ***** Not Used
C1 26 DK GRN Cruise Control Inhibit Output
C1 27 DK GRN/WHT A/C Clutch Relay Control
C1 28 YEL/BLK Shift Solenoid B Control
C1 29 RED Transmission Pressure Switch C Input
C1 30 DK BLU Transmission Pressure Switch B Input
C1 31 PNK Transmission Pressure Switch A Input
C1 32 WHT Transmission Range Switch Parity Input
C1 33 GRY Transmission Range Switch C Input
C1 34 YEL Transmission Range Switch B Input
C1 35 ORG/BLK Power Steering Pressure Switch Input
C1 36 PPL Torque Converter Clutch Brake Switch Input
C1 37 RED/BLK Transmission Pressure Control Solenoid
C1 38 LT BLU/WHT Transmission Pressure Control Solenoid
C1 39-45 ***** Not Used
C1 46 ORG/BLK Manifold Absolute Pressure Sesnor Signal
C1 47 PPL/WHT Heated Oxygen Sensor Input High
C1 48 TAN/WHT Heated Oxygen Sensor Input Low
C1 49 & 50 ***** Not Used
C1 51 BLK Fuel Tank Pressure Sensor Signal
C1 52 & 53 ***** Not Used
C1 54 GRY Generator Terminal F Feedback
C1 55-57 ***** Not Used
C1 58 PPL Serial Data (Class II)
C1 59 PPL Serial Data (Class II)
C1 60 BLK/WHT Powertrain Control Module Ground
C1 61 ORG Powertrain Control Module Battery Voltage
C1 62 GRY EGR Position Sensor Reference Voltage
C1 63 GRY Throttle Position Sensor Reference Voltage
C1 64 GRY Manifold Absolute Pressure Sensor Reference Voltage
C1 65 ***** Not Used
C1 66 GRY Fuel Tank Pressure Sensor Reference Voltage
C1 67 ***** Not Used
C1 68 DK BLU Throttle Position Sensor Input
C1 69 LT GRN Manifold Absolute Pressure Sensor Input
C1 70 ***** Not Used
C1 71 BLK Intake Air Temperature Signal
C1 72 BLK Transmission Fluid Temperature Signal
C1 73 ***** Not Used
C1 74 BLK/WHT Transmission Range Switch A Input
C1 75 ***** Not Used
C1 76 GRY Extended Travel Brake Switch
C1 77 LT BLU/BLK Cruise Control Engaged Input
C1 78-80 ***** Not Used
C2 1-3 ***** Not Used
C2 4 BLK Camshaft Position Sensor Input High
C2 5 LT BLU/BLK Crankshaft Position 24x Sensor Input High
C2 6 ***** Not Used
C2 7 YEL Vehicle Speed Sensor Input High
C2 8 PPL Vehicle Speed Sensor Input Low
C2 9 BLK Fuel Injector No. 1 Control
C2 10 LT GRN/BLK Fuel Injector No. 2 Control
C2 11 RED/BLK Fuel Injector No. 7 Control
C2 12 PNK/BLK Fuel Injector No. 3 Control
C2 13 LT BLU/BLK Fuel Injector No. 4 Control
C2 14-16 ***** Not Used
C2 17 BLK/WHT Fuel Injector No. 5 Control
C2 18 YEL/BLK Fuel Injector No. 6 Control
C2 19 & 20 ***** Not Used
C2 21 BLK/WHT Powertrain Control Module Ground
C2 22 DK BLU/WHT Fuel Injector No. 8 Control
C2 23 ***** Not Used
C2 24 DK GRN/WHT EVAP Control Solenoid Control
C2 25 DK GRN/WHT Vehicle Speed Sensor Output
C2 26 BRN/WHT Malfunction Indicator Light Control
C2 27 TAN/BLK Delivered Torque Output
C2 28 WHT Tachometer Output
C2 29 WHT EVAP Vent Valve Control
C2 30 & 31 ***** Not Used
C2 32 DK GRN Cooling Fan Low Speed Control
C2 33 DK BLU Cooling Fan High Speed Control
C2 34 PNK/BLK EGR Valve Ignition Voltage
C2 35 GRY EGR Valve Control
C2 36 DK GRN/WHT Fuel Pump Relay Control
C2 37 PNK Powertrain Control Module Ignition Feed
C2 38-43 ***** Not Used
C2 44 PPL/WHT Crankshaft Position 4x Sensor Input High
C2 45 YEL Mass Airflow Sensor Input
C2 46 ORN/BLK Desired Torgue Input
C2 47 ***** Not Used
C2 48 RED/BLK Reference Input Low
C2 49 WHT Ignition Control Feedback
C2 50 ***** Not Used
C2 51 TAN/BLK Bypass Spark Output
C2 51-56 ***** Not Used
C2 57 TAN/BLK Engine Oil Pressure Sensor Input
C2 58 BRN Engine Oil Level Sensor Input
C2 59 ***** Not Used
C2 60 BLK/WHT Powertrain Control Module Ground
C2 61 ***** Not Used
C2 62 DK BLU Knock Sensor Input
C2 63 & 64 ***** Not Used
C2 65 TAN Rear Bank Heated Oxygen Sensor Input High
C2 66 PPL Rear Bank Heated Oxygen Sensor Input Low
C2 67 PPL/WHT Preconverter Heated Oxygen Sensor Input High
C2 68 TAN/WHT Preconverter Heated Oxygen Sensor Input Low
C2 69 PPL Front Bank Heated Oxygen Sensor Input High
C2 70 TAN Front Bank Heated Oxygen Sensor Input Low
C2 71-73 ***** Not Used
C2 74 YEL Engine Coolant Temperature Sensor Input
C2 75 DK GRN Fuel Tank Pressure Sensor Input
C2 76 TAN Intake Air Temperature Sensor Input
C2 77 BRN EGR Valve Feedback
C2 78-80 ***** Not Used
(1) See Fig 1 .
Factory Service Tools

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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.

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