FixVault

Removal & Installation

Some ECM models use a CALPAC as well as a PROM. See Fig 1 . The CALPAC must also be removed from replaced 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: ECM With PROM & CALPAC
G2781Courtesy of GENERAL MOTORS CORP.