Buick Camshaft Issue Causes No-Start Condition
This bulletin applies to 2011-2017 Buick Regal, 2010-2018 LaCrosse and 2013-2017 Verano vehicles equipped with 2.0 liter, 2.2L or 2.4L engines. The maintenance light may be on with Diagnostic Trouble Code P0017 setting on a properly timed engine with a crank/no-start condition.
This may be due to a camshaft reluctor that has moved on the camshaft. The reluctor is a press fit and is not indexed to the camshaft. An overheat condition may contribute to the concern, causing the reluctor to spin/shift on the camshaft when hot. On “rare” occasions, the engine may crank and not run and not set any codes. This could be caused by a camshaft reluctor being spun/shifted or a faulty camshaft position sensor or solenoid. It could also be caused by a faulty mass airflow sensor.
To check the exhaust cam reluctor position on 2.4 LES engines only, with the exhaust camshaft positioned so that the valves for #4 cylinder are at maximum lift/fully opened, the reluctor should be flush/parallel to the rocker cover gasket surface. If the reluctor position does not line up correctly, the exhaust camshaft must be replaced.
If the engine cranks but does not run and no codes are set, unplug one sensor or solenoid and crank the engine to see if it runs. Plug the sensor or solenoid back in and unplug a different one and crank the engine to see if it starts. Perform this procedure for these sensors: intake camshaft position sensor, exhaust cam position solenoid, intake cam position solenoid, exhaust cam position sensor and mass airflow sensor. If the engine cranks and runs with one of these sensors or solenoids unplugged, then typically that sensor/solenoid is faulty.
If the engine starts and runs with one of the camshaft position sensors unplugged, then the camshaft position sensor that is unplugged is faulty or the reluctor has spun. Replace the suspect sensor or swap the intake and exhaust cam position sensors with each other. Note: if the intake and exhaust sensors are swapped with each other and the engine starts and runs with both sensors plugged in, the cam position sensor currently in the intake location is faulty.
In this example, the reluctor is not level with the rocker cover gasket surface.