July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Removal & Installation

Some ECM models use a CAL-PAK as well as a PROM. See Fig 1. If replacing ECM, remove CAL-PAK from old ECM and install in new ECM. Removal and replacement procedures for CAL-PAK are same as for PROM. See PROGRAMMABLE READ-ONLY MEMORY (PROM) . If units are improperly installed, grounding diagnostic test lead will set Code 52.

Fig 1: Locating PROM & CAL-PAK On ECM

Courtesy of GENERAL MOTORS CORP.