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.
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 line connectors before replacing the PCM.

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

1.
Problem verification:

Problem verification
?1.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?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), or press the engine start/stop button to select the OFF mode.

?5.
Turn the ignition switch to ON (II), or press the engine start/stop button to select 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 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), or press the engine start/stop button to select the OFF mode.

?3.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?4.
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
     
     
     
If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.
     
NO
     
     
     
Troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.?