Removal & Installation
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. 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.