SERVICE MANUAL UPDATE-SEC. 8A VEH. SPEED SENSOR DIAGNOSIS

MODELS/YEARS 1989 CUTLASS CIERA

Add the following symptom to the Symptom Tables for the 1989 Cutlass Ciera Service Manual, Section 8A, pages 33-3, 33-4, 33-5 and 33-7 for the Vehicle Speed Sensor Diagnosis.

Speedometer is Do Test G inaccurate

On pages 33-4 and 33-7 insert the following test.

G:SPEEDOMETER IS INACCURATE

1. Connect a scan tool to the ALDL connector. Drive the vehicle, observe the Speedometer and compare it to the vehicle speed shown on the scan tool.

* If both the speedometer and scan tool display the same speed, check for correct tire size, VSS drive gears and ECM PROM.

* If scan tool and speedometer do not display the same speed, replace Instrument Cluster.

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.