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 engine code "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.