P0021: A Camshaft Position - Timing Over-Advanced (Bank 2)

What it means

The bank 2 intake camshaft is more advanced than commanded, or the actuator does not respond as expected. Often caused by stuck-open oil control valves, sludge in VVT passages, or low oil pressure.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The bank 2 intake camshaft actuator uses engine oil to advance or retard the camshaft as the engine control module commands. This code sets when the bank 2 intake cam is more advanced than expected, or its position does not follow the commanded timing.

Common causes

Most likely first.

1. Oil control valve stuck (advance)
2. Sludge in VVT passages

Symptoms

• Check engine light on
• Power loss especially in mid-rpm range
• Possible rough idle or stalling
• Increased fuel consumption

How to diagnose it

1. Save freeze-frame data and compare commanded with actual bank 2 intake cam timing in live data to confirm the over-advanced condition.
2. Check engine oil level, condition, and service history because low or degraded oil can disrupt variable valve timing.
3. Inspect the bank 2 intake oil control valve connector and wiring, then check for related actuator or cam correlation codes.
4. Test the bank 2 intake oil control valve and its circuit using the manufacturer's procedure, checking whether the valve is sticking or its command is unreliable.
5. If the valve and circuit pass, inspect oil passages for restriction and verify cam timing and phaser operation according to the manufacturer's procedure.

Common fixes

• Correct low or overdue engine oil and use the specified oil.
• Repair damaged wiring or connector faults at the bank 2 intake oil control valve.
• Clean or replace a confirmed sticking bank 2 intake oil control valve.
• Clear restricted VVT oil passages or repair a failed cam phaser or misaligned timing components as indicated by testing.

Can I keep driving?

Limit driving if the engine runs roughly, stalls, or loses substantial power; avoid high engine speeds and heavy loads. Incorrect cam timing can worsen fuel use and may lead to further timing or engine damage.