DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681 & P1683: Pcm Memory: Description
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) electrically erasable programmable read only memory (EEPROM) contains data which is essential for operating the engine and transmission. The PCM continuously tests the integrity of this data.