Sensor Fools the ECM
This bulletin applies to 2013-2014 Buick Encore vehicles equipped with a 4-cylinder engine. The concern may involve an intermittent engine no-crank condition.
If the ignition key is cycled off and back on, the engine may crank. The condition may be caused by the ECM receiving an intermittent exhaust camshaft position (CMP) sensor signal as soon as the ignition is turned on. This results in the ECM not sending a crank request signal because it has determined that the engine is already running.
According to GM, the intake camshaft position (CMP) sensor will not cause this intermittent no-crank condition. If the intake CMP sensor has a fault, it will set a DTC.
According to GM, do not replace the exhaust CMP sensor based solely on the description of this condition. Perform the following actions:
1. Connect a scan tool to the vehicle.
2. Turn on the ignition with the engine off.
3. Perform the diagnostic system check.
If any DTC is set, refer to the DTC list in the service manual. Select engine data. With the ignition on and the engine off, observe one of the following active counter parameters for incrementing:
- Exhaust CMP Active Counter; or Exhaust Camshaft Position Active Counter. If the active counter parameter is incrementing, replace the exhaust CMP sensor.