PCM CNTRL Relay Circuit Malfunction
- Ignition OFF, disconnect the PCM CNTRL relay.
- With the ignition OFF and the scan tool disconnected, open and close the drivers door, and wait 30 seconds. Test for less than 1.5 Ω between the ground circuit terminal 85 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
- Ensure the parking brake is applied and the transmission is in PARK. Momentarily install a 40A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. The starter solenoid should engage and the engine should begin cranking.
- If the solenoid does not engage, test the starter control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the starter motor.
- Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
- With the transmission range selector in park or neutral, cycle the ignition between the OFF and CRANK position. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the PCM CNTRL relay.