The attaching page of this bulletin is to replace the ECM wiring diagram (page 2 of 3) on page 6E3-A-5 in section 6E3 "Driveability And Emissions" of the 1990 "A" carline with 3300 (VIN N) Oldsmobile and Buick 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.