PCM EPROM

DESCRIPTION

The PCM contains an EPROM (Electrically Programmable Read Only Memory) that contains the calibration information used by the PCM to control fueling, idle speed, ignition timing, transaxle shifts and emissions. This calibration information is based on various aspects of the vehicle such as engine size, vehicle weight, transaxle type, final drive ratio, etc.


PROGRAMMING OPERATION

The EPROM is programmed (Flashed) with this critical information. Replacement PCM's used for service come without the programming, which must be performed by the technician using the latest diagnostic tools and programs. Additionally, in certain situations, the diagnosis may require the technician to reprogram (Flash) the PCM in an attempt to eliminate a DTC or condition. Therefore, it is crucial that the latest service publications (bulletins, service manuals, etc.) be referenced for information concerning any new procedures or EPROM programs.

If the current program or an attempted reprogramming fails on the PCM, it will set DTC P0602. Refer to DTC P0602.