This bulletin applies to a handful of GM models including 2013-1014 Buick Encore, 2009-2011 Chevy Aveo, 2011-2014 Chevy Cruze, 2012-2014 Chevy Sonic and 2013-2014 Chevy Trax, all equipped with a four-cylinder engine.
Some customers may complain about an intermittent engine no-crank. They may also comment that if they cycle the ignition switch off and then back on, the engine cranks. This 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. DO NOT replace the exhaust CMP sensor based solely on the description of this condition.
The intake camshaft position sensor will not cause this intermittent no-crank condition. If the intake CMP sensor has a fault, it will set a DTC.
1. Connect a scan tool to the vehicle.
2. Turn the ignition on, with engine off.
3. Perform the diagnostic system check.
If any DTC is set, refer to theDTC list. With the ignition on and engine off, observe one of the following Active Counter parameters for incrementing:
- Exhaust CMP Active Counter.
- Exhaust camshaft position active counter.
If the Active Counter parameter is incrementing, replace the exhaust CMP sensor.
