DeVille V8-4.6L VIN Y (1998)
Powertrain Control Module: Component Tests and General Diagnostics
Powertrain Control Module and Flashing the EPROM
IMPORTANT: The service PCM will not contain data. The EPROM must be flashed after the service PCM is installed.
Diagnostic Procedures
This powertrain has very complex components with equally complex operating characteristics. Therefore, it is essential that the Powertrain diagnostic
procedures given in this and other database sections be used for diagnosis before any repairs are made. While the PCM may appear on the surface to be
the source of a problem, it may, in fact, be operating properly based on incorrect inputs it receives. Powertrain diagnostic procedures are designed to
arrive at the CORRECT repair as QUICKLY as possible. DO NOT, under any circumstances, replace a PCM unless directed to do so by diagnostic
procedures in the database, other service information sources, or through technical assistance.
Service / Replacement Of The PCM
Service of the PCM will consist of either replacement of the PCM and/or flashing the EPROM. If a diagnostic procedure calls for the PCM to be
replaced, the PCM should be checked first to see if it is the correct part. The EPROM can also be flashed when called for. When flashing the EPROM,
also refer to the latest service publications for updated programming procedures and information. After replacement of a PCM and/or flashing the
EPROM, clear PCM DTCs and check the vehicle for proper operation. Poor engine performance, surging, loss of cruise control, improper SERVICE
ENGINE SOON MIL operation, no starts, and/or hard starts may be caused by an improperly flashed EPROM, in which case DTC P0602 may set and
the vehicle may not start.
NOTICE: In order to prevent internal PCM damage, leave the ignition OFF when installing or removing the PCM connectors and disconnecting or
reconnecting the power to the PCM (battery cable, PCM pigtail, PCM fuse, jumper cables, etc.).
The EPROM and the EEPROM are soldered into the PCM and cannot be serviced separately.
