In cold weather, some owners of 1988-91 Pontiac Bonnevilles may experience a condition where the outside air temperature reading on the control head may rise rapidly during extended periods of idling. When the vehicle begins to move, the temperature display may rapidly drop to the actual temperature.
A new control head, part number 16178768, has been released for service. This new head contains software that changes the filtering update rate of the outside air temperature program. Refer to the Service Manual for the proper replacement procedure.
The above listed part only corrects this service condition. Any other system complaint should be serviced with the service part listed in the parts catalog.
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.