For 1990-2009 cars

# SERVICE MANUAL UPDATE-SEC. 8A VEHICLE SPEED SENSOR

#### SUBJECT: ELECTRICAL DIAGNOSIS VEHICLE SPEED SENSOR - SPEEDOMETER IS INACCURATE

#### MODELS/YEARS: 1991-93 EIGHTY EIGHT AND NINETY EIGHT

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

The following revised text in the 1991-93 Eighty Eight/Ninety Eight Service Manuals, Page 8A-33-1, should replace the following given text for proper system diagnosis.

#### THE TEXT WHICH STATES:

o If scan tool and speedometer do not display the same speed, replace the instrument cluster (see Section 8C).

#### SHOULD BE REPLACED WITH:

o If scan tool and speedometer do not display the same speed, do test B.

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.