Skyhawk L4-121 2.0L VIN 1 TBI (1988)
Crankshaft Position Sensor: Technical Service Bulletins
Engine Controls - Crankshaft Sensor R&R Precaution
Bulletin
89-6-10
Date
May, '89
Ref. No.
89-127-6
Corp. Ref. No.
936509
SUBJECT:
IMPROPER CRANKSHAFT SENSOR REPLACEMENTS DUE TO OIL ON THE SENSOR
MODELS AFFECTED: 1988-89 CENTURY AND REGALS WITH 2.8L (VIN W) 3.1L (VIN T) ENGINES WITH DIRECT IGNITION SYSTEM
(DIS) 1988-89 SKYHAWK WITH 2.OL (VIN 1) ENGINE WITH DIRECT IGNITION SYSTEM (DIS)
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.
