OBD codes / P0021
P0021
ModerateCamshaft Position Timing Over-Advanced (Bank 2)
P0021 is usually drivable short-term, but address it soon — check oil level and condition immediately, since that alone fixes many cases. If the cause is a worn phaser or timing chain, continued driving can make it worse.
What this code means
P0021 is the Bank 2 version of P0011: the intake cam timing on the cylinder-2 side is more advanced than the computer commanded, and it can't pull it back. Variable timing runs on oil pressure through a control solenoid, so the most common and cheapest cause is oil — low level, the wrong viscosity, or dirty/overdue oil clogging the small passages. Next is a stuck VVT/VCT solenoid or clogged screen; less often a worn phaser or stretched timing chain. An oil change is a smart first step.
Symptoms you might notice
- Rough idle or stalling
- Loss of power or hesitation
- Rattle from the engine at start-up
- Reduced fuel economy
- Check-engine light
What it costs to fix
Typical range: $60–$1,500 · about ~0.3–6 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Oil change (when low/dirty oil is the cause) | $30–$100 | ~0.3–0.6 hrs |
| VVT/VCT solenoid (oil-control valve) | $30–$150 | ~0.5–2 hrs |
| Camshaft phaser | $150–$500 | ~3–6 hrs |
The low end assumes the cause is simply low or dirty oil — which genuinely does fix a fair number of these, but isn't guaranteed. The typical repair is the VVT solenoid (modest); a worn phaser or stretched timing chain is the major, high-end job. Get a chain/phaser repair diagnosed before committing.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0021 for my exact vehicle →
How to fix P0021
Moderate — doable at home with common tools and patience
- Rule out the oil first
Over-advanced timing on Bank 2 most often traces back to oil that can't do its job — low, dirty, or the wrong viscosity. Check the dipstick and change the oil if it's dark or overdue; this alone resolves many P0021s.
- Compare commanded and actual cam angle on Bank 2
With a scan tool, watch Bank 2's desired versus actual cam timing at idle and under light revving. Timing stuck advanced even when the computer commands base position means the phaser or solenoid is physically hanging up rather than an electrical fault.
- Remove and examine the Bank 2 VVT solenoid
Pull the oil-control solenoid on the cylinder-2 side and inspect the mesh screen. Debris on the screen explains a sticking solenoid and is a warning that sludge may also be circulating through the phaser itself.
- Replace a sticking solenoid
Bench-test with 12 volts if you want confirmation, but a solenoid with a lazy plunger or dirty screen is cheap enough to replace outright. Clear the code and drive a full warm-up cycle to see if the fix holds.
- Escalate persistent codes to a mechanical inspection
If P0021 keeps returning on clean oil and a fresh solenoid, the Bank 2 phaser may be worn or the chain stretched. Confirming that means opening the timing cover — have a shop verify it before parts money goes any further.
DIY or shop? Oil service, scan-tool checks, and the solenoid swap are all reasonable driveway work, with the caveat that the Bank 2 solenoid can be buried on transverse V6 engines. Phaser or timing-chain verification belongs at a shop — it requires timing-cover removal and precise re-timing, where a mistake is far costlier than the diagnostic fee.
Tools for the DIY steps: OBD-II scan tool with live data · Oil and filter (manufacturer-spec viscosity) · Socket set · Parts cleaner · 12V test leads
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0021.
Frequently asked
Can I drive with P0021?
Short-term usually yes, but check your oil right away. If it's just oil, it's trivial; if it's a worn phaser or timing chain, continued driving can worsen it. Get it diagnosed if an oil change doesn't clear it.
Can low oil cause P0021?
Yes — it's one of the most common causes. The variable-timing system runs on oil pressure through tiny passages, so low, dirty, or wrong-grade oil readily triggers it. An oil change with the correct viscosity is a smart first move.
Is P0021 the same as P0011?
Same fault, opposite bank: P0011 is the intake cam over-advanced on Bank 1, P0021 is the same on Bank 2 (the cylinder-2 side). Causes and fixes are identical: oil, solenoid, then phaser/chain.
How much does it cost to fix P0021?
From an oil change to a major repair. Oil and solenoid fixes are cheap-to-modest; a camshaft phaser or timing chain is a big labor job. Diagnose before assuming the worst.
Seeing P0021 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0021 for my vehicleRelated trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0021 from your phone — see our honest guide to the best OBD2 Bluetooth adapters.
Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.