Action Taken By PCM

WARNING: This page is about a different car, the 2002 GMC Cab & Chassis Sierra and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

PCM performs the following actions if DTC is set:

For California emission equipped vehicles, the PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met. For Non-California emission equipped vehicles, the MIL is not illuminated.
The PCM commands maximum line capacity.
The PCM inhibits the TCC engagement.
The PCM inhibits 4th gear if in hot mode.
The PCM freezes shift adapts.
The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame (California only) and failure records (California and Federal).
The PCM stores the DTC P1870 in PCM history during the second consecutive trip (California) or the first trip (Federal) in which the conditions for setting the DTC are met.