Engine Controls - Updated Speed Sensor Diagnosis

89Oldsmobile08

SUBJECT: SERVICE MANUAL UPDATE - SECTION 8A, VEHICLE SPEED SENSOR DIAGNOSIS


MODELS/YEARS: 1989 CUTLASS CIERA
NUMBER: 89-T-86

CORP. REF. NO: 938122

DATE: JULY 1989

SECTION: 8A
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.