The following represents revised information for SECTION 5E1 or 5A4 in 1990-92 Light Duty Truck Model Service Manuals with 4WAL.
This information replaces the information found under "Diagnosis" in SECTION 5E1 or 5A4. Use this chart when diagnosing a code 61, 62, or 63 condition.
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.