DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 & P2610: Pcm Memory/Programming Malfunction: Description
WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
This diagnostic applies to internal microprocessor integrity conditions within the Powertrain Control Module (PCM). This diagnostic also addresses if the PCM is not programmed.