AMBIENT TEMP. DISPLAY IS INACCURATE (NEW P/N RELEASED)

SUBJECT: AMBIENT TEMPERATURE DISPLAY INACCURATE (NEW SERVICE MBIENT TEMPERATURE SENSOR)

MODELS AFFECTED: 1991 PARK AVENUE/ULTRA WITH CJ2 ----------------------------------------------------------------------------

THIS BULLETIN HAS BEEN REVISED DUE TO A PART NUMBER CHANGE AND SUPERSEDES BUICK BULLETIN NO. 91-1-3.

CONDITION:

---------- The ambient temperature display may indicate an inaccurate outside temperature one of two ways.

1. An outside temperature of 85-140- Fahrenheit is displayed regardless of actual outside temperature. If the outside air temperature is low, the result will be poor heater performance.

2. The ambient temperature display consistently reads 10-15 F below the actual air temperature. Both heater and A/C performance could be affected by this condition.

CORRECTION:

----------- A new ambient temperature sensor has been released for service. Part Number 16169194 is currently available from GMSPO.

After replacement of the sensor, the display should be updated. To do this follow the on-board diagnostics chart shown under the Dual Air Conditioning (CJ2) section of the service manual. Go down to Override (02 C). Then scroll down to 119 F. At this point press either the warm or cool button and the update will be complete. Failure to complete this update procedure may result in a display reading the same as the removed sensor. The system will update itself only after the vehicle is driven for some time (30-40 min.) or the vehicle has been sitting for 6 hrs.

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation No.: T5225

Labor Time: .3 hr.

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.