Removal & Installation
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Rally Camper Special, 1994 GMC Rally, and 1994 GMC Forward Control. However, it is still accessible from the selected car via links, so may be relevant.
Some PCM's use a CALPAC as well as a PROM. See Fig 1. The CALPAC must also be removed from old PCM and installed in new one. Removal and replacement procedures for CALPAC are same as for PROM. See PROGRAMMABLE READ-ONLY MEMORY (PROM) . If units are installed improperly, grounding diagnostic test lead will set Code 52.