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

NOTE: If the problem does not return after clearing the DTC, or if this DTC is stored intermittently, check for loose terminals at the IGP line connectors before you replace the ECM/PCM.

Turn the ignition switch ON (II).
Clear the DTC with the HDS.
Start the engine, and let it idle 30 seconds.
Turn the ignition switch OFF.
Start the engine, and let it idle 30 seconds.
Turn the ignition switch OFF.
Turn the ignition switch ON (II).
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0685 indicated?
1. YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
2. NO - Intermittent failure, system is OK at this time.