DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0685

DTC P0685 : ECM/PCM Power Control Circuit/Internal Circuit Malfunction

NOTE:
* Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.
* If the problem doesn't return after you clear the DTC, or if this DTC is stored intermittently, check for loose terminals at the IGP line connectors before replacing the ECM/PCM.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Start the engine, and let it idle for 30 seconds.

-4. Turn the ignition switch to LOCK (0).

-5. Turn the ignition switch to ON (II).

-6. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0685 indicated?
-YES- The failure is duplicated. Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
-NO- Intermittent failure. Check the following items:
* PGM-FI main relay 1
* PGM-FI main fuse
* Poor connections or loose terminals between the ECM/PCM and the under-hood fuse/relay box
* Poor or loose ECM/PCM ground terminals and connections
* Poor or loose battery cables and connections
* Check the battery

Repair verification:

-1. Start the engine, and let it idle for 30 seconds.

-2. Turn the ignition switch to LOCK (0).

-3. Turn the ignition switch to ON (II).

-4. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0685 indicated?
-YES- If the ECM/PCM was updated, substitute a known-good ECM/PCM Service and Repair, then recheck. If the ECM/PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.