ELECTRONIC FUEL INJECTION ECM SERVICE PRECAUTIONS

While performing service on the ECM of an electronic fuel injection equipped vehicle, it is imperative that the ignition switch is in the "off" position.

Internal ECM damage may occur if the ignition switch is left in the "on" position, and the ECM power is disconnected or connected. Battery cables, ECM fuse, or any other power feed to the ECM must be serviced with the ignition "off." This procedure should also be observed if it becomes necessary to "jump-start" a vehicle with a low battery.

If the ECM has been damaged in this fashion, a run-down battery condition will be observed. There will be no noticeable performance loss.

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.