OBD-II Trouble Code Description for P0021 GMC

“A” Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)

What does this mean?

OBD2 Code P0021 GM definition:
A code P0021 GM definition:the VVT (variable valve timing) or VCT (variable camshaft timing) components and the car’s PCM (powertrain control module, also called an ECM). That consists of a few different components but the P0021 GM DTC specifically definition:the camshaft (cam) timing. In this case, if the cam timing is above a set limit (over-advanced), the engine light will be illluminated and the code will be set. The “A” camshaft is either the intake, left, or front camshaft. A P0021 GM engine code is basically the same as a P0011 GM code, except this is for Bank 2, not Bank 1.

Symptoms

Possible sumptoms of OBD code P0021 GM
Most likely a P0021 GM DTC will result in one of the following: hard starting, poor idle, and/or stalling. There are potentially other symptoms as well. Of course, when trouble codes are set, the MIL (malfunction indicator lamp, a.k.a. the check engine light) illuminates.

Causes

Possible causes of OBD code P0021 GM
A P0021 GM DTC trouble code may be caused by one or more of the following:

Possible Solutions

This DTC code is a result of a mechanical fault of the VCT unit or related components, so there is no need for electrical diagnosis. Refer to vehicle specific repair manual to perform component tests for the VCT unit. Notes: Dealer techs have advanced tools and the ability to follow detailed troubleshooting steps, including the ability to test components using a scan tool.

Related Codes

P0010 GM P0011 GM P0012 GM P0020 GM P0022 GM