SERVICE MANUAL UPDATE-SEC. 8A DETONATION SENSOR CIRCUIT

SUBJECT: SECTION 8A - DETONATION (KNOCK) SENSOR CIRCUIT

VEHICLES AFFECTED: 1991 "Y" MODEL WITH 5.7L (VIN J, RPO LTS)

The identification of the Electronic Control Module (ECM) Connector D (Brn) for the Knock Sensor (Terminal 20, Circuit 496) is incorrect. It should be identified as Connector B (Red), Terminal 20, Circuit 496.

The following is a revised schematic for the Sequential Fuel Injection: V8 VIN J for Section 8A-22-3.

Please update your copies of the 1991 Service Manuals.

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.