P0020
Powertrain"A" Camshaft Position - Actuator Circuit (Bank 2)
The ECU watches the electrical circuit that drives the Bank 2 camshaft phaser, the bit that advances and retards your valve timing on the fly. When it sends a command to that actuator and either gets no response or the wrong voltage back, it logs P0020. For you it means the variable valve timing on one side of the engine isn't being controlled properly, so the engine can't fine-tune itself for smoothness and economy the way it should.
ⓘ Information only. This page provides general educational information about fault code P0020. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0020 mean?
P0020 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: "A" Camshaft Position - Actuator Circuit (Bank 2).
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on, sometimes the only thing you'll notice
- • Lumpy or uneven idle, usually worse once the engine has warmed through
- • Flat spots or hesitation when you put your foot down
- • Fuel economy drops off a bit, more obvious on regular town driving
- • Stalling at low revs, the kind that catches you out pulling up at a junction
- • A faint rattle from the timing end on start-up, particularly on cold mornings
Possible causes
Causes commonly associated with P0020, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Faulty VVT solenoid (oil control valve) on Bank 2. This is the usual offender, the coil inside goes open circuit or the valve sticks
- 2. Dirty or low engine oil. The phaser is oil-driven, and old sludgy oil or a low level chokes it. Worth checking before you touch a spanner
- 3. Damaged wiring or a broken connector pin in the Bank 2 actuator circuit, common where looms run near hot exhaust
- 4. Corroded or loose plug at the solenoid or back at the ECU, often a green crusty pin
- 5. The camshaft actuator (phaser) itself worn or seized on Bank 2
- 6. Worn timing chain or a tired tensioner letting the cam timing drift out of range, more likely on higher-mileage engines
- 7. ECU fault or a software glitch, rare, so leave this last
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Check the oil level and condition before anything else. If it's black, thin, or sitting low, the solenoid can't do its job. Sort that and a fair few of these clear on their own
- 2. Pull every stored code. P0020 rarely turns up alone, and a misfire or timing correlation code sitting alongside it changes what you chase first
- 3. Unplug the Bank 2 VVT solenoid and check the connector and the few inches of loom behind it for chafing, melt marks, or corroded pins
- 4. Measure the solenoid resistance with a multimeter against the manufacturer's figures, often somewhere around 6 to 15 ohms depending on engine. Out of spec means the coil's gone
- 5. With the connector back on, check for supply voltage and a switching signal at the solenoid while the engine runs. Power and command present but no actuator movement points at the phaser itself
- 6. If wiring, oil and solenoid all check out, look at the timing chain and tensioner condition before condemning the actuator
Common questions about P0020
How do I know if it's the solenoid, the wiring, or something worse on my car? +
Start cheap and work up. Check the oil first, because a low or filthy level can mimic the whole fault. Next unplug the Bank 2 solenoid and check resistance with a multimeter, if it's way off the maker's spec or reads open, that's your part. If resistance is fine, wiggle-test the connector and loom while watching live data for the solenoid command. A clean reading on the solenoid but the cam timing still won't move usually means the phaser itself, and that's where it gets expensive. The presence of a misfire code (P0300) alongside it often hints at timing actually drifting rather than just an electrical fault.
Can I sort this myself without a garage? +
Often yes for the common causes. An oil and filter change is straightforward, and the VVT solenoid on most engines is one or two bolts and a plug, with the part costing roughly £30 to £90 aftermarket. Cleaning a corroded connector costs nothing but time. Where it stops being a home job is circuit testing, which needs a meter and a scanner, or anything involving the timing chain, which means covers off and proper tools.
If I just clear the code, does it stay gone? +
Depends entirely on what caused it. Clear it after a genuine fix, like a new solenoid or fresh oil, and it'll stay off. Clear it with the fault still present and it'll come straight back, sometimes within minutes of the engine reaching temperature and the VVT trying to operate. Clearing a P0020 is a way to confirm you've fixed it, not a fix in itself.
What happens if I just leave it? +
You can usually drive on it short-term, but I wouldn't make a habit of it. The stalling at low revs is the real concern, dropping dead pulling out onto a roundabout is no joke. You'll also lose a touch of economy and the engine will feel flat. If the underlying cause is a starved oil supply or a worn chain rather than a dead solenoid, ignoring it lets the wear carry on, and that turns a cheap fix into a big bill. Get the oil checked at minimum.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →