SERVICE MANUAL UPDATE-SEC. 8A VEHICLE SPEED SENSOR

SUBJECT: ELECTRICAL SYSTEMS MANUAL UPDATE - ELECTRICAL DIAGNOSIS - VEHICLE SPEED SENSOR "SPEEDOMETER IS INACCURATE"

MODELS AFFECTED: 1991-93 PARK AVENUE/ULTRA AND LESABRE MODELS

Diagnosis for Test A "SPEEDOMETER IS INACCURATE" symptom found in the above mentioned service manuals has been revised to avoid any confusion and misdiagnosis.

The following revised text should replace the following given text for proper system diagnosis.

BUICK

1991 Park Avenue ESM, Page 78; and 1991 LeSabre ESM, Page 72, "TEST A: VEHICLE SPEED OUTPUT TEST" add the following text to the test:

o If all measurements are correct, do Test B.

1992 Park Avenue ESM, Page 82 1992 LeSabre ESM, Page 80 1993 LeSabre/Park Avenue ESM, Page 185, "SYMPTOM/DIAGNOSIS GUIDE"

THE BEADING WHICH STATES:

If the Speedometer and scan tool display different speeds, replace the Instrument Cluster see 4.

SHOULD BE REPLACED WITH:

If the Speedometer and scan tool display different speeds, do Test A.

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.