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squall ... 11/4/2012
2007 Mercedes Benz E63 AMG Base 8 Cyl 6.3L - Engine
My check engine light came on and I took it by Auto Zone to pull the code and it said P0021 cam shaft position sensor.
Is this a DYI or do I nee to take it to the shop. when I google it, it keep coming back as a crank shaft position sensor. the car is running find with 67.000 miles
1 Answer
  • Jimm
    Jimm 11/4/2012
    A code P0021 refers to 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 DTC specifically refers to 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 engine code is basically the same as a P0011 code, except this is for Bank 2, not Bank 1.

    Potential Symptoms
    Most likely a P0021 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.

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

    Incorrect camshaft timing
    Wiring problems (harness/wiring) in intake timing control valve control solenoid system
    Continuous oil flow to VCT piston chamber
    Failed timing valve control solenoid (stuck open)

    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.

    A camshaft position sensor is not difficult to replace - check the 'How-To-Guides' feature on the AutoMD website.
    Try the many on-line auto parts sources, such as; or for the replacement parts

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