SERVICING OF ELECTRONIC FUEL INJECTOR CONTROL MODULES

A new model control module (ECM) is being released for usage in 19821/2 EFI equipped vehicles. This new model utilizes two (2) circuit boards instead of three (3) circuit boards used on present models.

The most distinguishing difference between a two (2) board ECM and three (3) board ECM is physical size and harness connector locations. The two (2) board ECM is thinner than the present model. Also, the harness connectors are connected to the ECM in-line instead of being slightly staggered as they are at present.

The design of the calibration unit (PROM) has also been slightly modified. The modifications mostly affect how the PROM is mounted in the ECM; therefore, the service of the PROM is also affected.

New service procedures are included in this bulletin. The two (2) board ECM will only be used on 2.5L EFI L4. When servicing ECM or PROM, insure that ignition switch is in "OFF" position.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.