GM Service Manual Online
For 1990-2009 cars only

INACCURATE SPEEDOMETER READING AT SPEEDS ABOVE 55 MPH

Model and Year: 1987-88 CELEBRITY MODELS

Condition:

----------

The speedometer on 1987-88 Celebrity models may be inaccurate on the high end of the scale, generally at speeds well above 55 MPH. The speedometer should be accurate at 55 MPH (plus or minus 2 MPH) and below.

Correction:

----------

1. Insure that the odometer reading is correct by driving over a known distance, such as freeway mile markers. This will insure that the tires and driven gear are correct. Incorrect tires or driven gear will cause both inaccurate speedometer readings at all speeds, and an inaccurate odometer. If the odometer reading is not correct, repair that condition first before doing Step 2.

2. The speedometer cluster assembly should be sent to an authorized Delco repair station, stating "inaccurate speedometer reading at high MPH". The cluster will receive a new speedometer with a revised calibration procedure.

Use applicable labor operations.

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.