DTC P0607: PCM Backup Circuit Malfunction

Reset the PCM (see HOW TO RESET THE PCM ).
Turn the ignition switch OFF.
Turn the ignition switch ON (II).
Is DTC P0607 indicated?
1. YES -Substitute a known-good PCM and recheck (see HOW TO SUBSTITUTE THE PCM FOR TESTING ). If the symptom/indication goes away, replace the original PCM.
2. NO -Go to step 4.
Cycle the ignition switch OFF and ON (II) five times.
Check for a DTC or a Temporary DTC with the scan tool or the HDS.
Is DTC P0607 indicated?
1. YES -Inspect the No. 13 BACK UP (7.5A) fuse. If the fuse is OK, repair open in VBU wire between the driver's under-dash fuse/relay box and the PCM.
2. NO -Intermittent failure, system is OK at this time. A low battery can cause this problem. Ask the customer if the engine had to be jump-started recently.