For 1990-2009 cars

### Circuit Description

The PCM monitors ignition voltage on circuit 439 when powered up. The purpose of this diagnostic trouble code is to detect an unstable ignition voltage to the PCM.

### Conditions for Setting the DTC

This DTC sets from an internal PCM failure. The TCM sees battery voltage out of range high or low.

### Test Description

Check for DTC P0562 and P0563. If no DTCs are present, replace the PCM.

If DTC P1635 is also set, diagnose DTC P1635 first.