P0603

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The Vehicle Control Module (VCM) contains a memory area where it stores certain data it needs to save when the ignition is turned OFF. This area is called Keep Alive Memory; This diagnostic test monitors the VCMs keep alive memory for a loss or unintended change of data. If such a condition occurs, DTC P0603 sets.


Conditions for Setting the DTC

If the checksum data of the Keep Alive Memory stored at power-down does not match the checksum data of the Keep Alive Memory at power-up and the data read from memory does not match the data which is stored in the check memory function, DTC P0603 will set.


Action Taken When the DTC Sets

^ The VCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

^ The VCM will record the operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.


Conditions for Clearing the MIL/DTC

^ The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.

^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.


Diagnostic Aids

If the battery has been disconnected for any reason DTC P06O3 will set. The VCM checks the memory at power-up. If the memory changes, it will reset. An intermittent loss of power or ground to the VCM will also cause a reset.