Description of OBD-II DTC Trouble Code
Generic: “A” Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)
Nissan: Camshaft variable timing control – Bank 2 – performance
What is the meaning of this?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles, including but not limited to Toyota, VW, Ford, Dodge, Honda, Chevrolet, Hyundai, Audi, Acura, etc.
A P0021 code refers to the VVT (variable valve timing) or VCT (variable camshaft timing) components and the car’s PCM (powertrain control module) or ECM (engine control module). VVT is a technology used in the engine to allow it to achieve greater power or efficiency at different running points.
This code specifically relates to the camshaft (cam) timing. If the cam timing exceeds a certain limit (over-advanced), the engine light will illuminate and the code will be set. The “A” camshaft can be either the intake, left, or front camshaft. A P0021 engine code is essentially the same as a P0011 code, except it pertains to Bank 2 instead of Bank 1.
Possible Symptoms
Most likely, a P0021 DTC will result in one of the following: hard starting, poor idle, and/or stalling. There may be other potential symptoms as well. When trouble codes are set, the MIL (malfunction indicator lamp, also known as the check engine light) will illuminate.
Possible Causes
A P0021 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 in the VCT unit or related components, so there is no need for electrical diagnosis. Refer to the vehicle-specific repair manual to perform component tests for the VCT unit. Notes: Dealer technicians have advanced tools and the ability to follow detailed troubleshooting steps, including the ability to test components using a scan tool.
Other related DTCs: P0010 – P0011 – P0012 – P0020 – P0022
