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Engine mechanicalSeverity Medium: diagnose soon

P0021"A" Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)

What it means

The intake (or left/front) camshaft, bank 2, is more advanced than the ECU asked for, or doesn't follow the command. Most often an oil problem or a sticking oil control valve.

Symptoms

  • Check engine light
  • Rough idle or stalling
  • Loss of power or poor fuel economy
  • Rattle on start-up (worn phaser)

Common causes

  • Low oil level, wrong oil viscosity or sludge
  • Sticking oil control valve or blocked filter screen
  • Worn cam phaser
  • Stretched timing chain or wrong timing

What to check first

  1. Check oil level, grade and condition first
  2. Compare desired and actual cam angle in live data
  3. Remove and inspect the oil control valve and its screen
Can I drive with P0021? Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0021: questions and answers

What does P0021 mean?

P0021: "A" Camshaft Position – Timing Over-Advanced or System Performance (Bank 2). The intake (or left/front) camshaft, bank 2, is more advanced than the ECU asked for, or doesn't follow the command. Most often an oil problem or a sticking oil control valve.

What are the symptoms of P0021?

Check engine light. Rough idle or stalling. Loss of power or poor fuel economy. Rattle on start-up (worn phaser).

What causes P0021?

Low oil level, wrong oil viscosity or sludge. Sticking oil control valve or blocked filter screen. Worn cam phaser. Stretched timing chain or wrong timing.

How do you diagnose P0021?

1. Check oil level, grade and condition first 2. Compare desired and actual cam angle in live data 3. Remove and inspect the oil control valve and its screen

Can I drive with P0021?

Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.