P052

Circuit Description

This diagnostic test monitors the PCM's keep alive memory for a loss or unintended change of data. If such a condition occurs, Code P052/P109 will set.

Test Condition(s)

Test continuously.

Failure Condition(s)

Keep alive memory checksum does not match previous checksum.

Action Taken

None.

Notes on Intermittents

If the battery has been disconnected for any reason Code P052/P109 will set.

The PCM keeps a running check on the memory; if memory changes it resets.

Code P052/P109 may set while keying 'OFF' in diagnostics. If the IPC is sending new information to the PCM when the ignition is turned 'OFF', the PCM may think it has been switched, causing a reset.