P0021 Code – “A” Camshaft Position – Timing Over-Advanced or System

Meaning:

P0021 happens when the camshaft timing for bank 2 is above and beyond the limit set by the ECM
The P0021 code indicates an over-advanced condition of the camshaft timing

The camshaft timing for bank 2 is above and beyond the limit set by the ECM. This causes an over-advanced condition that occurs either during retarding or advancing of the camshaft timing.

Main Symptoms:

  • Check Engine Light comes on
  • Hard starting
  • Poor idle
  • Car may run rough or stall
  • Poor fuel economy
  • Car may fail emission test

Possible Causes:

  • Camshaft remains advanced despite ECM commanding it to retard
  • Bank 2 oil control solenoid may be clogged or stuck
  • Oil may be too thick and is thus blocking passages in bank 2
  • Wiring problems in VCT/VVT
  • Oil continuously flows to VCT piston chamber

Diagnostic Steps:

  • Check that engine oil is clean and has the recommended viscosity
  • Visually inspect wiring in the CVT system
  • Pull engine codes and live data using advanced diagnostic tool

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