DTC Troubleshooting: P0685 (135)
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.
  • If the problem doesn't return after you clear the DTC, or it this DTC is stored intermittently, check for loose terminals at the IGP line connectors before replacing the ECM/PCM.
  1. Turn the ignition switch to ON (II).
  1. Clear the DTC with the HDS.
  1. Start the engine, then let it idle for 30 seconds.
  1. Turn the ignition switch to LOCK (0).
  1. Start the engine, then let it idle for 30 seconds.
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II).
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0685 indicated?
YES -
Go to Step 9 .
NO -
Intermittent failure, the system is OK at this time.■
  1. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
  1. Start the engine, then let it idle for 30 seconds.
  1. Turn the ignition switch to LOCK (0).
  1. Start the engine, then let it idle for 30 seconds.
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II).
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0685 indicated?
YES -
If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 10 . If the ECM/PCM was substituted, go to Step 1 .
NO -
If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■