P0011 means the camshaft on bank 1 is more advanced than the engine computer asked for. Variable valve timing is driven by engine oil through a small solenoid, so the usual causes are oil related: old oil, the wrong grade, a low level, or a solenoid that has stuck. Diagnose soon and drive gently. Indicative UK repair cost is £80 to £600.
Variable valve timing moves the camshaft a few degrees either side of its base position while the engine is running, trading low-speed torque against high-speed breathing. It does that hydraulically: the computer opens a solenoid, engine oil flows into the cam phaser, and the phaser rotates. Every part of that sentence depends on clean oil arriving at the right pressure, which is why this code has more to do with servicing than almost anything else in this library.
Can I drive with P0011?
Diagnose soon, drive gently. You may notice a rough idle, a flat spot low in the rev range, or marginally worse economy. On some engines you will notice nothing at all beyond the light. This is not a code that strands people. The argument for dealing with it is that the same poor oil supply which stops a phaser doing as it is told is also what wears a timing chain and its tensioner, so a P0011 ignored for a year has a habit of being followed by a considerably more expensive code.
What P0011 means for your MOT
The lamp is the certain route to a failure. It is a major defect under section 8.2.1.2 of the DVSA MOT inspection manual for petrol cars first used on or after 1 July 2003, and under 8.2.2.2 for diesels first used on or after 1 July 2008.
Beyond that, it is worth being careful about what anybody promises you. Valve timing that is away from where it should be does change how completely the mixture burns, so it can move the hydrocarbon and lambda figures that the petrol emissions test measures, and both of those carry their own major defect. Whether it moves them far enough to actually fail is specific to the engine and the degree of error, and nobody can tell you in advance. What is certain is the lamp.
What usually causes it
- A faulty variable valve timing solenoid. The solenoid carries a fine mesh screen that blocks with sludge, and the spool inside it sticks with age. Over-advanced generally means it is letting oil through when it should be holding it back. On many engines it is a single-bolt part and a sensible first move.
- Low or dirty engine oil. This is not filler advice on this particular code, it is the operating mechanism. The wrong viscosity, oil well past its interval, or a level that has quietly dropped will all stop a phaser responding properly. It is also the one cause here you can eliminate this afternoon for the price of a service.
- Wear in the timing components. A phaser with worn internal vanes cannot hold the position it is commanded to, and a chain that has stretched shifts the baseline the whole system is working from.
What it costs to fix in the UK
£80 to £600. An oil and filter change together with a solenoid is the bottom of that. A cam phaser on its own is the middle. A phaser and a chain kit together is the top, and on engines where the chain is at the back of the block it goes beyond it.
Because the cheapest possible answer here is a service, it is worth knowing what a car diagnostic costs in the UK and weighing that against simply having the oil done properly first.
These are indicative UK ranges for guidance only. Actual causes and prices vary by vehicle, and a stored code points to a system, not always the exact part.
What to check first
- Start with the oil, genuinely. Level, condition, and whether it is the grade the manufacturer specifies rather than whatever was cheapest. If the service history is patchy or the oil is black and thin, change it and the filter, clear the code and use the car for a week. That is not a fob-off, it is the most likely fix on the list.
- Take the solenoid out and look at its screen. A blocked mesh is immediately obvious once it is in your hand, and it tells you both what the fault is and why it happened.
- Compare commanded cam angle with actual on live data. At idle and at raised revs. A phaser that will not return to its base position, or overshoots what it is asked for, is behaving exactly as this code describes.
- Listen from cold before committing to a phaser. If there is a rattle on start-up as well as this code, the chain is in the conversation too, and the order in which the work is done then matters a great deal to the final bill.
Related codes
- P0016, crankshaft and camshaft correlation. The code to read if there is start-up rattle alongside this one, because it is the one that points at the chain.
- P0340, camshaft position sensor circuit. Same system seen from the measurement side rather than the actuation side.
- P0300, random or multiple cylinder misfire. Valve timing that is away from target upsets every cylinder at once, so a misfire code often keeps this one company.
Get it narrowed down before you spend
A stored code tells you which system is unhappy, not which part has failed. If you want it narrowed down before you spend anything, send the code and your symptoms and a mechanic will read them personally. Quick Diagnosis is £20, and if we can't help, you don't pay.
Written by the First Diagnostic mechanic. Over a decade in the trade: a VW-only workshop running diagnostics and electrical repair, then BMW-only through to full engine rebuilds. Now an independent all-makes workshop, plus building and wiring drift cars for competition, including trackside work as head mechanic. More about who reads your codes.