What is the difference between P0011 and P0012?

They describe the same camshaft on the same bank failing in opposite directions. P0011 means the camshaft is phased further advanced than the control unit commanded; P0012 means it is further retarded. Because most intake phasers rest in the fully retarded position and are advanced by oil pressure, P0012 is characteristically the fault where oil never reaches the phaser at all, from a blocked screen, a stuck control valve or low oil pressure. P0012 also has one cause P0011 rarely has: a stretched or jumped timing chain retards the camshaft mechanically and looks identical to the sensors.

Can a stretched timing chain cause P0012?

Yes, and it is the reason not to dismiss this code as a solenoid fault. A chain that has stretched or skipped a tooth retards the camshaft relative to the crankshaft, which is exactly what the code describes, and the sensors cannot distinguish that from a phaser that will not advance. The clues are a rattle for a second or two after a cold start, hard starting, and a camshaft-to-crankshaft correlation code such as P0016 stored alongside. Have the timing checked properly rather than guessed at, because a chain in that condition can skip further and on an interference engine that means bent valves.

Can I drive with a P0012 code?

Only as far as a garage. If the cause is a stuck oil control valve the car is simply down on power and nothing worse is happening, but if it is a timing chain the risk is engine damage rather than inconvenience, and you cannot tell the difference from behind the wheel. Any rattle from the timing drive at start-up, hard starting, or reduced power mode means stop using the car normally.

Will P0012 fail an MOT?

Yes. The illuminated engine management lamp is a major defect for petrol cars first used on or after 1 July 2003 and diesels from 1 July 2008. There is a second route to failure with this one: the emissions test needs the engine held at a fast idle of roughly 2,500 to 3,000 rpm, and a car that has dropped into reduced power mode may not reach it, which means the test cannot be completed and that is a major failure in itself.

Powertrain code · standard

P0012Camshaft timing stuck too far retarded, bank 1

Standard definition: "A" Camshaft Position - Timing Over-Retarded (Bank 1)

Last updated 27 July 2026

Quick answer

The intake camshaft on bank one is sitting behind the position the control unit asked for. It shares most of its causes with P0011, with one important addition: cam timing can also be retarded mechanically by a chain that has stretched or jumped, and that is the version you cannot ignore.

How the car works this out

The check is the same comparison as P0011 — commanded phaser angle against the angle measured from the camshaft and crankshaft sensors — but the direction of the error matters. On most engines the intake phaser sits in the fully retarded position at rest, held there by a locking pin, and the engine advances it under oil pressure once running. That means P0012 is characteristically the failure where the phaser is not being driven at all: no oil reaching it, or a control valve that never opens. It is also, unfortunately, what a timing chain that has stretched or skipped a tooth looks like, because a stretched chain retards the camshaft mechanically and the sensors cannot tell the difference.

What you might notice

A rough idle and a hesitant, breathless engine, particularly higher up the rev range
Reduced power and heavier fuel consumption
A rattle from the timing drive on start-up, if the chain is the cause
Long cranking before the engine catches
The engine management lamp on, sometimes with reduced power mode

What causes it

Most likely first. A code names the check that failed, not the part that failed it, so more than one of these can produce the same number.

1An oil control valve stuck closed, or its filter screen blocked, so no oil reaches the phaser to advance itCommon
How to check: Remove the valve, check the gauze screen and bench test the spool with a battery to confirm it moves and returns freely.
2Dirty oil, oil of the wrong viscosity, or an overdue oil changeCommon
How to check: Change it with the specified grade and filter, then clear the code and drive it. This alone resolves a large share of these.
3Low oil pressure at idle, from a low level, a worn pump or a blocked pickupPossible
4A timing chain that has stretched or jumped a tooth, retarding the camshaft mechanicallyPossible
How to check: This is the cause that matters. Listen for a rattle in the first seconds after a cold start, look for a correlation code such as P0016 stored alongside, and have the cam timing checked against the manufacturer's marks with the phaser commanded fully off. A chain far enough gone to retard the timing is close to skipping further.
5A worn phaser whose internal vanes or locking pin no longer hold positionPossible
6Wiring or connector damage at the oil control valve, so it is never energisedPossible
How to check: Check for battery voltage at the connector with the ignition on and measure the solenoid's resistance against specification.

What to do about it

1Listen to the engine from cold, standing outside it with the bonnet up. A rattle in the first seconds after start-up moves this from a solenoid job to a timing chain job, and changes how urgent it is.
2Change the oil and filter to the exact specification and clean the oil control valve screen. If the fault is hydraulic this fixes it, and if it is not you have lost nothing.
3Have the cam timing verified against the manufacturer's data rather than assumed. This is the one code in the family where a mechanical cause is a real possibility.
4Do not keep driving it on the assumption it is only a solenoid if there is any rattle, any hard starting, or a correlation code stored alongside.

Can you keep driving?

Only to a garage

If this is an oil control valve, nothing dramatic is happening and the car is merely down on power. If it is a stretched or slipping timing chain, the next thing that happens is the chain skipping further, and on an interference engine — which covers nearly everything built in the last thirty years — that puts valves into pistons and can write off the engine. You cannot tell which from the driving seat, so treat it as a trip to a garage rather than a fortnight of commuting.

Will it fail an MOT?

Beyond the lamp, which is a major defect on petrol cars first used from 1 July 2003 and diesels from 1 July 2008, this code carries a practical risk at the test itself. The petrol emissions check requires the engine to be held at a fast idle, around 2,500 to 3,000 rpm, while the readings settle. A car in reduced power mode may refuse to rev that far, and an emissions test that cannot be completed is recorded as a major failure of its own. Cam timing sitting retarded also shifts the hydrocarbon and lambda readings directly.

The light this turns on

Engine management lightThe engine management system has found a fault it cannot correct and has stored a code for it. The car will usually still drive, but an illuminated engine light is an automatic MOT failure on petrol cars first used from 1 July 2003 and diesels from 1 July 2008.

Common questions

What is the difference between P0011 and P0012?: They describe the same camshaft on the same bank failing in opposite directions. P0011 means the camshaft is phased further advanced than the control unit commanded; P0012 means it is further retarded. Because most intake phasers rest in the fully retarded position and are advanced by oil pressure, P0012 is characteristically the fault where oil never reaches the phaser at all, from a blocked screen, a stuck control valve or low oil pressure. P0012 also has one cause P0011 rarely has: a stretched or jumped timing chain retards the camshaft mechanically and looks identical to the sensors.
Can a stretched timing chain cause P0012?: Yes, and it is the reason not to dismiss this code as a solenoid fault. A chain that has stretched or skipped a tooth retards the camshaft relative to the crankshaft, which is exactly what the code describes, and the sensors cannot distinguish that from a phaser that will not advance. The clues are a rattle for a second or two after a cold start, hard starting, and a camshaft-to-crankshaft correlation code such as P0016 stored alongside. Have the timing checked properly rather than guessed at, because a chain in that condition can skip further and on an interference engine that means bent valves.
Can I drive with a P0012 code?: Only as far as a garage. If the cause is a stuck oil control valve the car is simply down on power and nothing worse is happening, but if it is a timing chain the risk is engine damage rather than inconvenience, and you cannot tell the difference from behind the wheel. Any rattle from the timing drive at start-up, hard starting, or reduced power mode means stop using the car normally.
Will P0012 fail an MOT?: Yes. The illuminated engine management lamp is a major defect for petrol cars first used on or after 1 July 2003 and diesels from 1 July 2008. There is a second route to failure with this one: the emissions test needs the engine held at a fast idle of roughly 2,500 to 3,000 rpm, and a car that has dropped into reduced power mode may not reach it, which means the test cannot be completed and that is a major failure in itself.

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