DTC P0685: PCM Power Control Circuit/Internal Circuit Malfunction

NOTE: 

• Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions SystemsHow to Troubleshoot the CVT System(CVT System) .
• If the problem does not return after you clear the DTC, or if this DTC is stored intermittently, check for loose terminals at the IGP(ECU)/FI MAIIN RLY OUT line connectors before replacing the PCM.

• 1. Problem verification:

  1. Turn the vehicle to the ON mode.

  2. Clear the DTC with the HDS.

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

  4. Turn the vehicle to the OFF (LOCK) mode.

  5. Turn the vehicle to the ON mode.

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

  DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
  P0685 PCM Power Control Circuit/Internal Circuit Malfunction

  Is DTC P0685 indicated?

  YES 

  The failure is duplicated. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0685 goes away and the PCM was updated, troubleshooting is complete. If DTC P0685 goes away and the PCM was substituted, replace the original PCM .

  NO 

  Intermittent failure. Check the following items. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

  • 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 12 volt battery cables and connections
  • Check the 12 volt battery