Engine Controls - Crankshaft Sensor Replacement Caution
89chevy17Number: 89-130-6E
Section: 6E
Date: APRIL, 1989
Subject: IMPROPER CRANKSHAFT SENSOR REPLACEMENTS DUE TO OIL ON THE SENSOR
Model and Year: 1988-89 A, J, L CARS WITH 2.0L (VIN CODE 1) OR 2.8L (VIN CODE W) ENGINES
TO: ALL CHEVROLET DEALERS
Condition:
Crankshaft sensors returned from dealerships show a very high percentage of NTF (No Trouble Found) units.
Cause:
The sensors are usually replaced because of a driver comment of intermittent reduced performance, hesitation, or no start. When diagnosing the ignition system, the crankshaft sensor is found to be wet with oil, and is replaced. The oil, however, will not cause an operational problem with the ignition system, and the sensor should not be replaced for this reason.
The likely cause for the performance condition is an intermittent connection to the sensor. Replacing the sensor may fix the condition for a time, but the vehicle could return at a later time with the same condition.
Correction:
1. DO NOT replace the sensor because oil is found in the sensor. The sensor should only be replaced if diagnosis (such as CAMS or the Service Manual procedure) indicates that it is defective. The sensor may also be replaced if an oil leak is the original concern (this is very rare).
2. Check the wire harness connector to the sensor for proper contact. The wire terminals, or the connector body itself, may be replaced if necessary.