Engine

P0021 — Intake Camshaft Timing Over-Advanced (Bank 2)

Severity: medium Drive with care, to a shop

What P0021 means

The ECM compares commanded and actual intake camshaft position on bank 2 using camshaft and crankshaft sensor signals. Timing is adjusted by an oil-pressure-driven phaser that an oil control solenoid operates. P0021 sets when the cam sits further advanced than the ECM requested.

Symptoms

  • Check engine light on
  • Rough or unstable idle
  • Hard starting
  • Reduced power
  • Worse fuel economy
  • Possible stalling

Possible causes

  1. Faulty VVT oil control solenoid
  2. Low, dirty or wrong-viscosity engine oil
  3. Stretched timing chain or misaligned timing
  4. Damaged wiring or connector at the VVT solenoid
  5. Worn or sticking cam phaser
  6. Faulty camshaft position sensor (less likely)

How to diagnose

  1. Scan for codes and review freeze frame data for other faults
  2. Check oil level, condition and viscosity
  3. Inspect the bank 2 VVT solenoid wiring and connector, test power and ground
  4. Compare desired and actual cam angle in live data
  5. Command the VVT solenoid with a scan tool and check the response
  6. Test solenoid resistance and inspect its screen for debris
  7. Check timing chain stretch and timing mark alignment
  8. Verify the cam sensor signal with a scope

Common fixes

  • Change oil and filter with the specified viscosity
  • Replace or clean the VVT solenoid
  • Repair wiring and connectors
  • Replace the timing chain, tensioners and cam phaser
  • Replace the camshaft sensor if confirmed faulty

P0021 on different brands

Ford · manuals
Ford lists this as P0021:00, intake camshaft position timing over-advanced on bank 2; it describes the monitor condition detected, not a confirmed failed part.

Questions and answers

Can I drive with a P0021 code?

Short, gentle trips to a shop are usually fine. If the engine runs rough, stalls or you hear chain rattle, stop driving to avoid major engine damage.

Can bad oil cause P0021?

Yes, it's one of the most common causes. The phaser works on oil pressure, so low, dirty or wrong-viscosity oil upsets timing control.

What does bank 2 mean?

It's the cylinder bank that doesn't contain cylinder 1. Only V-type and flat engines have one, so inline engines normally won't show this code.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.