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Removal & Installation

Some ECM's use a CALPAC as well as a PROM. See Fig 1. The CALPAC must also be removed from old ECM and installed in new one. Removal and replacement procedures for CALPAC are same as for PROM. See PROGRAMMABLE READ-ONLY MEMORY (PROM) in this article. If units are installed improperly, grounding diagnostic test lead will set Code 52.

Fig 1: Locating PROM & CALPAC On ECM

Courtesy of GENERAL MOTORS CORP.