INTERMITTENT NO START CONDITION (REPLACE SENSOR)

MODELS AFFECTED: 1987-88 CENTURYS WITH 2.5L ENGINES (VIN CODE R) 1987 SOMERSETS WITH 2.5L ENGINES (VIN CODE U) 1987-88 SKYLARKS WITH 2.5L ENGINES (VIN CODE U)

Condition

Some vehicles may experience an intermittent no-start condition ("cranks but won't run"), due to an intermittent electrical connection between the Direct Ignition System (DIS) module and crankshaft sensor. The no-start condition is most likely to occur when the engine is cold.

Examination of warranty material has shown that this condition is being improperly diagnosed as a DIS module condition, resulting in repeat comments and customer dissatistaction. Because the integrity of the connection between the module and crankshaft sensor is provided by the sensor terminal design, replacing the DIS module will not provide a lasting fix for the intermittent condition.

Correction:

----------- When a comment of an intermittent no-start condition occurs and the usual diagnostic procedures do not identify a cause, replace the DIS crankshaft sensor. The DIS module should be replaced only in instances where previous replacement of the DIS crankshaft sensor did not correct an intermittent no-start condition.

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.