The PCM reset mode allows the scan tool to clear any emission related diagnostic information from the PCM. When resetting the PCM, a DTC P1000 will be stored until all OBD II system monitors or components have been tested to satisfy a trip without any other faults occurring.
The following items occur when the PCM Reset is performed:
PCM fault codes may be cleared by using the scan tool or disconnecting the negative battery cable for a minimum of 15 seconds.
KEEP ALIVE MEMORY (KAM) RESET
The Keep Alive Memory (KAM) contains the adaptive factors used by the processor to compensate for component tolerances and wear. It should not be routinely cleared during diagnosis. If and emissions related part is replaced during repair, the KAM must be cleared. Failure to clear the KAM may cause severe driveability problems, since the correction factor for the old component will be applied to the new component.
To clear the KAM disconnect the negative battery cable for at least 5 minuets. After the memory is cleared and the battery is reconnected, the vehicle must be driven a couple of miles so that the PCM may relearn the needed correction factors. The distance to be driven depends on the engine and vehicle, but all drives should include steady throttle cruise on the open roads. Certain driveability problems may be noted during the drive because the adaptive factors are not yet functioning.