An engine management warning light illuminated on a car dashboard
Insights by Stedmans Garage

Vehicle fault codes, explained.

Plain-English guides to the VAG fault codes we see most often in the workshop: what each one means, the symptoms to expect, what causes it and how it gets fixed.

A code tells you where to look. Not what has failed.

When the engine management light comes on, the ECU stores a code describing the reading that fell outside its expected range. That is a starting point, not a diagnosis, as the same code can have several very different causes. These guides explain what each one means in practice. If you already have a code, search for it below.

44 codes

P0010Camshaft Position Actuator Circuit (Bank 1)Learn more→P0016Camshaft / Crankshaft Correlation (Bank 1)Learn more→P0101MAF Sensor Range / PerformanceLearn more→P0102MAF Sensor Circuit Low InputLearn more→P0103MAF Sensor Circuit High InputLearn more→P0105MAP Sensor Circuit MalfunctionLearn more→P0106MAP Sensor Range / PerformanceLearn more→P0107MAP Sensor Circuit Low InputLearn more→P0108MAP Sensor Circuit High InputLearn more→P0121Throttle Position Sensor Range / PerformanceLearn more→P0122Throttle Position Sensor 'A' Circuit Low InputLearn more→P0130O2 Sensor Circuit (Bank 1, Sensor 1)Learn more→P0131O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)Learn more→P0132O2 Sensor Circuit High Voltage (Bank 1, Sensor 1)Learn more→P0133O2 Sensor Slow Response (Bank 1, Sensor 1)Learn more→P0134O2 Sensor No Activity Detected (Bank 1, Sensor 1)Learn more→P0135O2 Sensor Heater Circuit (Bank 1, Sensor 1)Learn more→P0136O2 Sensor Circuit (Bank 1, Sensor 2)Learn more→P0137O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)Learn more→P0138O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)Learn more→P0141O2 Sensor Heater Circuit (Bank 1, Sensor 2)Learn more→P0170Fuel Trim Malfunction (Bank 1)Learn more→P0171System Too Lean (Bank 1)Learn more→P0172System Too Rich (Bank 1)Learn more→P0201Cylinder 1 Injector CircuitLearn more→P0202Cylinder 2 Injector CircuitLearn more→P0203Cylinder 3 Injector CircuitLearn more→P0204Cylinder 4 Injector CircuitLearn more→P0299Turbocharger Underboost (Low Boost)Learn more→P0335Crankshaft Position Sensor CircuitLearn more→P0340Camshaft Position Sensor CircuitLearn more→P0341Camshaft Sensor Range / PerformanceLearn more→P0400EGR Flow MalfunctionLearn more→P0401EGR Flow InsufficientLearn more→P0402EGR Flow ExcessiveLearn more→P0403EGR System MalfunctionLearn more→P0404EGR Circuit Range / PerformanceLearn more→P0405EGR Sensor 'A' Circuit LowLearn more→P0700Transmission Control System (MIL Request)Learn more→P1101Upstream Lambda Voltage Low / LeakageLearn more→P1337Camshaft Position Sensor (G40) Short to GroundLearn more→P1338Camshaft Position Sensor (G40) Open Circuit / Short to B+Learn more→P1339Crank and Engine Speed Sensors Cross-ConnectedLearn more→P2015Intake Manifold Flap Sensor (Bank 1)Learn more→

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I recently bought a new car and wanted a third-party health check for peace of mind. The team were friendly, helpful and got me booked in quickly - even though my new car is an EV, which my previous garage didn't handle. They explained everything clearly and made the whole process easy. Great service all around.

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Since moving to the area we have been using Stedmans for a couple of years now and could not be happier with the service. They are courteous, prompt and attentive. It feels like a place with a strong sense of community, valuing customer satisfaction and building relationships. Fully recommended!

Adam Tomlinson

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A warm welcome as usual when collecting my car after a full service. They kept us updated by phone about tyre wear and confirmed the MOT had passed. I have used Stedmans for four years and intend to continue. They even do a pick-up service, so helpful when you are in your 80s. A garage I can trust to speak plainly about any problem and what it will cost to put right.

June-Eva S.

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Took my car in for a service, MOT and to check a few issues - including my own 'DIY attempt' at being a mechanic! From start to finish the team were brilliant: friendly, professional and reassuring. Fair pricing, clear communication and genuine care - you really feel your car is in safe hands. I wouldn't hesitate to recommend Stedmans.

Paul Sandell

Google review

Have been using Stedmans for years - amazing service, they are always happy to help and even go the extra mile. All staff are brilliant. An amazing local garage that you can trust.

Tyrone Bailey

Google review

I recently bought a new car and wanted a third-party health check for peace of mind. The team were friendly, helpful and got me booked in quickly - even though my new car is an EV, which my previous garage didn't handle. They explained everything clearly and made the whole process easy. Great service all around.

Johannes Asmussen

Google review

Since moving to the area we have been using Stedmans for a couple of years now and could not be happier with the service. They are courteous, prompt and attentive. It feels like a place with a strong sense of community, valuing customer satisfaction and building relationships. Fully recommended!

Adam Tomlinson

Google review

A warm welcome as usual when collecting my car after a full service. They kept us updated by phone about tyre wear and confirmed the MOT had passed. I have used Stedmans for four years and intend to continue. They even do a pick-up service, so helpful when you are in your 80s. A garage I can trust to speak plainly about any problem and what it will cost to put right.

June-Eva S.

Google review

Took my car in for a service, MOT and to check a few issues - including my own 'DIY attempt' at being a mechanic! From start to finish the team were brilliant: friendly, professional and reassuring. Fair pricing, clear communication and genuine care - you really feel your car is in safe hands. I wouldn't hesitate to recommend Stedmans.

Paul Sandell

Google review

Have been using Stedmans for years - amazing service, they are always happy to help and even go the extra mile. All staff are brilliant. An amazing local garage that you can trust.

Tyrone Bailey

Google review

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