This guide is reviewed against current UK timing-system and sensor-fault patterns, indicative repair-cost context, and DVSA MOT guidance where a timing or misfire fault affects test outcomes.
When your engine management light comes on and the scanner shows a timing, camshaft, crankshaft, or ignition coil code, the fault can range from a duff sensor to a stretched timing chain. These codes affect the engine's ability to know exactly where the pistons and valves are at any given moment, and without that information the engine runs poorly — or not at all. This guide covers the most common UK timing and sensor codes, what they actually point to, and how much they typically cost to fix in Britain.
Timing, cam, and crank sensor fault codes in the UK usually cost between £60 and £800 to fix depending on the cause. A failed sensor is cheap. A stretched timing chain or failed VVT actuator is significantly more. Because these faults affect engine timing, they can cause non-start, misfires, stalling, and MOT failure — so they should not be ignored.
This guide uses standard UK timing-system diagnosis patterns and common repair-cost bands to explain why these codes cover such a wide range of outcomes. It is intended to help you understand what a garage is telling you and question quotes intelligently, not replace hands-on testing. For how we explain diagnostics and review tools, see our editorial approach, customer reviews, and scanner recommendations.
Your engine uses several systems to keep valve and piston timing perfectly synchronised. Variable Valve Timing (VVT) actuators adjust camshaft position at different engine speeds for efficiency and power. Crankshaft position sensors tell the ECU where the bottom end of the engine is. Camshaft position sensors tell it where the top end is. When these systems disagree — or when a sensor fails — the ECU sets a fault code and the engine runs rough, stalls, or will not start at all.
Ignition coil codes (P0351–P0354) are related because they fire the spark plugs at the exact moment the timing system dictates. If the ECU cannot trust the timing data, it cannot fire the coils correctly, and misfires follow.
These codes relate to the Variable Valve Timing solenoid or actuator on the intake or exhaust camshaft. They are common on engines with hydraulically actuated VVT — which includes the majority of modern petrol engines sold in the UK.
P0016 is one of the most important codes in this group. It means the camshaft and crankshaft position sensors are not showing the expected relationship. This can indicate a stretched timing chain, a slipped timing belt, incorrect sensor installation, or a mechanical timing issue. On UK roads, P0016 on high-mileage chain-driven engines often points toward chain stretch that needs replacing.
These are extremely common on Vauxhall, Ford, and BMW models. A failed crank sensor can leave you stranded, so treat these as urgent.
These codes mean the ECU has detected a problem with the electrical circuit of a specific ignition coil. The coil may be dead, the wiring to it may be damaged, or the ECU driver may have failed. On most UK petrol cars, replacing the affected coil is straightforward and relatively cheap.
| Component | Typical UK cost (parts + labour) | Comment |
|---|---|---|
| Cam or crank sensor replacement | £60–£200 | Sensor itself is usually £20–£60; fitting is straightforward on most cars |
| VVT solenoid or actuator | £100–£400 | Solenoid can often be cleaned rather than replaced; actuator replacement is more involved |
| Ignition coil replacement | £30–£120 | Per coil. Often DIY-friendly on accessible engines |
| Timing chain replacement | £400–£800 | Labour-intensive. Common on Ford Zetec, Vauxhall, and BMW chain engines over 80k miles |
| Timing belt replacement | £300–£600 | Routine service item on belt-driven engines. Usually includes water pump |
| Wiring repair | £40–£120 | Depends on how much loom damage needs fixing |
A timing or sensor fault alone does not directly cause an MOT failure — the MOT checks emissions and safety, not individual fault codes. However, the symptoms they produce absolutely can. A misfiring engine will fail the emissions test. An engine that stalls intermittently is a safety concern. An engine management light that is on is likely to be noted. If the timing fault causes rough running, stalling, or a persistent misfire, treat MOT failure risk as high until the issue is resolved.
DIY-friendly: Ignition coil replacement (P0351–P0354) is often a five-minute job on accessible engines. Cam and crank sensor replacement is usually straightforward if you can reach the sensor. Cleaning a VVT solenoid is achievable with basic tools.
See a garage: P0016 (cam/crank correlation) should be diagnosed by a garage with the right tools to check chain stretch or belt timing. Timing chain replacement is a significant job that requires engine locking tools and expertise. Any code that causes non-start or stalling needs proper diagnosis before you start replacing parts.
When these faults appear alongside other warning systems, the diagnosis may extend beyond the timing system. Communication faults like U0100 or ABS warnings such as C0035 can present concurrently and should be ruled out rather than chasing timing parts alone.
Use your code and vehicle details to see likely causes, urgency, and realistic UK repair costs before spending money at a garage.
Get My AI Diagnostic Report — £1.59 →Disclaimer: Informational guidance only. Timing system faults can cause engine damage if ignored. If you see P0016, P0335, or P0340 alongside non-start, stalling, or misfires, get the vehicle checked promptly.