P1625

DTC P1625 PCM/ECM INTERNAL SYSTEM RESET




Circuit Description
The powertrain control module (PCM)/engine control module (ECM) has a memory area where it stores certain data it needs to save when the ignition is OFF. This diagnostic test monitors this memory for a loss or unintended change of data. If such a condition occurs, DTC P0603 will set.

Conditions for Setting the DTC
- Memory checksum does not match previous checksum.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- No message will be displayed.
- Clear keep alive memory locations.

Conditions for Clearing the DTC
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- PCM/ECM battery voltage is interrupted.

Diagnostic Aids
If the battery has been disconnected for any reason, DTC P1625 will set. The PCM/ECM keeps a running check on the memory. If the memory changes it will reset. An intermittent loss of power or ground to the PCM/ECM will cause a reset.

Steps 1 To 4:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.