DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0685

DTC P0685 : 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 PCM.

1. Problem verification:

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

-2. Clear the DTC with the HDS. How to Troubleshoot the Fuel And Emissions Systems

-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 PCM PCM Update if it does not have the latest software, or substitute a known-good 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 PCM and the under-hood fuse/relay box
* Poor or loose 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 PCM was updated, substitute a known-good PCM Service and Repair, then recheck. If the PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.