Audi warning lights: what each light means

Overheating or temperature warning light

Urgency: As soon as possibleRedSymbol: thermometer over wavy lines (coolant)

The temperature needle climbs towards the red zone or the coolant warning light comes on. It usually points to a lack of coolant, a leak, or a failing thermostat or water pump. Driving on can warp the cylinder head or damage the gasket.

What to do: Stop as soon as you can and switch the engine off. Do not open the coolant reservoir cap while it is hot. If coolant is missing, do not set off again until you have found the leak.

8 documented faults that trigger it in the Audi

• High severity: Failing water pump and cooling system leaks · 3.0 TDI V6 engine · A4 B7, A4 B8, A4 B9 and 15 more
• High severity: Timing belt and water pump · 1.6 TDI engine · A1 I, A3 II and A3 III
• High severity: Timing belt and water pump · 1.4 TDI engine · A1 I and A2
• Medium severity: Thermostat housing leak and water pump failure · 2.0 TSI / TFSI engine · A3 II, A3 III, A3 IV and 9 more
• Medium severity: Water pump and thermostat housing leak (EA211) · 1.2 and 1.4 TSI engine · A1 I and A3 III
• Medium severity: Leak at the thermostat housing and water pump · Audi 3.0 TFSI V6 engine · A4 B8, A5 I, A6 C6 and 6 more

And 2 more faults on the linked pages.

• Overheating on Audi: by model
• Overheating: general guide

Oil pressure warning light on

Urgency: As soon as possibleRedSymbol: oil can (an oil can with a drop)

The red oil-can warning light means the engine is not getting the oil pressure it needs. The cause may be a low oil level, a failing oil pump or a blocked oil circuit. With low pressure, parts such as the turbo, the bearings or the timing drive can wear out within minutes.

What to do: Stop the car as soon as it is safe and switch the engine off. Check the level with the dipstick and do not drive on if the light stays on: call a recovery truck.

2 documented faults that trigger it in the Audi

• High severity: High oil consumption · 2.0 TSI / TFSI engine · A3 II, A3 III, A4 B8 and 6 more
• Critical severity: Oil pump failure on the pumpe-düse 2.0 TDI · 2.0 TDI engine · A3 II and A6 C6

• Oil warning light: general guide

Coolant warning light on (low level or temperature)

Urgency: As soon as possibleRedSymbol: thermometer over wavy lines (fluid)

It is the symbol of a thermometer over wavy lines, which warns of a problem in the cooling circuit: low fluid level or excessive temperature. The colour changes by brand (red, yellow or blue) and the seriousness of the warning depends on it.

What to do: Slow down, stop on level, safe ground and switch the engine off. With the engine cold, check the level in the expansion tank and look for leaks; if the level drops again or the light persists, do not keep driving and call for assistance.

1 documented fault that triggers it in the Audi

• Medium severity: Coolant leaks from the water pump and thermostat module · 1.0 TSI / 1.5 TSI engine · A1 I, A1 II, A3 III and 3 more

• Coolant light: general guide

Airbag warning light on

Urgency: Garage soonRedSymbol: a seated person wearing a seat belt with a circle (the inflated airbag) in front; in some cars, the letters SRS or AIRBAG

The airbag warning light means the system has detected a fault and an airbag or seatbelt pretensioner may not deploy in a crash. Causes range from a connector under the seat to the control unit or the airbag itself.

What to do: Have it diagnosed as soon as possible and check with the VIN whether the car has any outstanding airbag recall.

11 documented faults that trigger it in the Audi

• Critical severity: Airbags and pretensioners with out-of-specification ignition mix (campaign for July to December 2016) · outside the engine · A1 I
• Critical severity: Driver's airbag inflator that can throw out metal fragments (2026 campaign, code 69R6) · outside the engine · A3 II
• High severity: Several one-off campaigns on seat anchorage and the front airbag (2018-2021) · outside the engine · A4 B9
• High severity: Campaign 68J1: faulty airbag control unit · outside the engine · Q4 e-tron
• Critical severity: Faulty dashboard that may prevent the front passenger airbag from deploying in the Audi A6 · outside the engine · A6 C8
• Critical severity: Incorrect mixture in airbag and pretensioner initiators (production from July to December 2016) · outside the engine · A8 D4

And 5 more faults on the linked pages.

• Airbag light on Audi: by model
• Airbag light: general guide

Electric parking brake warning

Urgency: Garage soonRedSymbol: letter P inside a circle in brackets, sometimes with an exclamation mark

Cars with an electric parking brake show a warning light or message when the caliper motor, its wiring or the control unit fails. The brake may not release or may not apply.

What to do: Do not rely on the handbrake if the warning appears: park on level ground and leave the car in gear. Have the system diagnosed.

3 documented faults that trigger it in the Audi

• Critical severity: Recalls for the rear brake hose and the sealing of the handbrake cable · outside the engine · A4 B6
• Critical severity: The electric parking brake could apply inappropriately · outside the engine · Q2
• Medium severity: Electronic parking brake that is hard to release · outside the engine · Q3 I

• Parking brake warning on Audi: by model
• Parking brake warning: general guide

Engine fault warning light (check engine)

Urgency: Garage soonYellow or amberSymbol: outline of an engine seen from the side, in yellow or orange

The orange engine-shaped warning light comes on when the ECU detects a fault affecting combustion or emissions. If it flashes, it usually points to misfires that can damage the catalytic converter.

What to do: If it stays on steadily, you can drive gently to a garage and ask for a fault code read-out. If it flashes or you notice a loss of power, slow down and get to a garage as soon as possible.

16 documented faults that trigger it in the Audi

• Critical severity: Timing chain stretch and tensioner failure (EA111) · 1.2 and 1.4 TSI engine · A1 I and A3 II
• Critical severity: Piston breakage and oil consumption in the 1.4 TSI twincharger · 1.2 and 1.4 TSI engine · A1 I and A3 II
• High severity: Wear of the high-pressure pump cam follower · VW 2.0 TFSI EA113 engine · A3 II, A4 B7 and TT II
• Critical severity: Timing chain and tensioner wear · 2.0 TSI / TFSI engine · A3 II, A4 B8, A5 I and 3 more
• Medium severity: Carbon build-up on the intake valves · 2.0 TSI / TFSI engine · A3 II, A3 III, A4 B8 and 6 more
• Medium severity: EGR valve clogged with carbon · 1.9 TDI engine · A3 I, A4 B5 and A6 C5

And 10 more faults on the linked pages.

• Engine warning light on Audi: by model
• Engine warning light: general guide

ESP warning light on or flashing

Urgency: Garage soonYellow or amberSymbol: the silhouette of a car with curved skid marks (swerving lines) beneath it, or the letters ESP, in amber or orange

The ESP light belongs to the electronic stability control, the system that brakes wheels individually and reduces power when the car starts to skid. It flashes while the system is intervening; if it stays on steadily, it usually indicates a fault (often a sensor) or that ESP has been switched off with its button.

What to do: If it flashes in a bend or on a wet road, ease off: ESP is working. If it stays on, switch off and restart, check the ESP OFF button has not been pressed and, if it persists, ask a garage for a fault code read-out.

7 documented faults that trigger it in the Audi

• High severity: Campaign 45BF: stability control module missing pump motor screws · outside the engine · Q4 e-tron
• High severity: Jerks and harsh shifts from the 7-speed S tronic dual-clutch gearbox · outside the engine · Q5 II
• Critical severity: Insufficient ESP and ABS diagnostic function on 2009 vehicles · outside the engine · A3 II
• Medium severity: ABS/ESP module or hydraulic unit failure · outside the engine · A3 I
• Medium severity: ABS/ESP warning light on because of sensors, with no real brake fault · outside the engine · A3 III
• Low severity: Instrument cluster and on-board electronics faults (pixels, ESP and airbag warning lights) · outside the engine · TT I

And 1 more fault on the linked pages.

• ESP light on Audi: by model
• ESP light: general guide

ABS or ESP warning light on

Urgency: Garage soonYellow or amberSymbol: the letters ABS, usually inside a circle, in amber or orange

It indicates a fault in the anti-lock braking or stability control system: often a dirty or damaged wheel speed sensor, its wiring or the hydraulic unit. The brakes still work, but without those aids.

What to do: Drive carefully, especially in the rain, and ask for a fault code read-out. It is often fixed with a wheel sensor.

6 documented faults that trigger it in the Audi

• High severity: Campaign 45BF: stability control module missing pump motor screws · outside the engine · Q4 e-tron
• Critical severity: Insufficient ESP and ABS diagnostic function on 2009 vehicles · outside the engine · A3 II
• Medium severity: ABS/ESP module or hydraulic unit failure · outside the engine · A3 I
• Medium severity: ABS/ESP warning light on because of sensors, with no real brake fault · outside the engine · A3 III
• Low severity: Instrument cluster and on-board electronics faults (pixels, ESP and airbag warning lights) · outside the engine · TT I
• Low severity: MMI screen, radio and on-board electronics faults · outside the engine · A5 I

• ABS/ESP light on Audi: by model
• ABS/ESP light: general guide

Particulate filter warning light (DPF)

Urgency: Garage soonYellow or amberSymbol: particulate filter symbol on the dashboard, normally amber; its design varies by manufacturer

On modern diesels it means the particulate filter is clogged with soot and has not been able to regenerate. It is common in cars used mostly for short town journeys, although it can also be caused by a sensor or by an injection or EGR fault.

What to do: If the handbook allows it, a 20-minute drive on a motorway at a steady speed can complete the regeneration. If the light stays on or you lose power, go to a garage.

4 documented faults that trigger it in the Audi

• Medium severity: Manipulated emissions software (dieselgate) and the subsequent update · 2.0 TDI engine · A3 II, A4 B8, Q3 I and 1 more
• Medium severity: Clogged particulate filter or faulty pressure sensor · 2.0 TDI engine · A3 II, A4 B8, Q3 I and 1 more
• Medium severity: Clogged particulate filter (DPF) · 1.6 TDI engine · A1 I, A3 II and A3 III
• Medium severity: Clogged particulate filter (DPF) · 1.4 TDI engine · A1 I

• DPF warning light on Audi: by model
• DPF warning light: general guide

Power steering warning light on

Urgency: Garage soonYellow or amberSymbol: steering wheel with an exclamation mark, yellow or orange if the fault is minor and red if it is more serious

A warning light showing a steering wheel and an exclamation mark that warns of a power steering fault. When it comes on, the steering can become very heavy, especially at low speed and when parking, although the steering does not lock. Depending on the colour, the fault is considered minor (orange or yellow) or more serious (red).

What to do: If the steering has suddenly gone very heavy or the light is red, stop in a safe place and call for assistance. If it is yellow or orange and the car is still controllable, drive slowly and carefully to the garage.

2 documented faults that trigger it in the Audi

• High severity: Premature wear of the track rod end ball joints (1999 campaign) · outside the engine · A4 B5
• Medium severity: Power steering warning after driving through heavy rain or flooded areas · outside the engine · A4 B8

• Steering light: general guide

EPC warning light on

Urgency: Garage soonYellow or amberSymbol: the letters EPC, in yellow or orange

EPC stands for Electronic Power Control. It is the yellow or orange warning light that Volkswagen group cars use to warn of a fault in the electronic system that governs the engine and the throttle. The ECU may then limit power and speed to protect the car.

What to do: Slow down, stop somewhere safe, switch the engine off and restart it. If the light stays on, ask a garage for a fault code read-out before replacing any part.

1 documented fault that triggers it in the Audi

• Medium severity: Turbo wastegate actuator failure · 1.2 and 1.4 TSI engine · A1 I, A3 II and A3 III

• EPC light: general guide

"Pollution control system faulty" message

Urgency: Garage soonYellow or amberSymbol: a text message on the dashboard ("anticontaminación defectuosa" or similar wording, in English "emissions system fault"), sometimes alongside an amber warning light

A common message on Peugeot, Citroën, DS and Opel cars from the Stellantis group. It appears when the ECU detects a fault in a component that controls emissions: the particulate filter, the EGR valve, the sensors, the AdBlue system or, on petrol engines, combustion problems.

What to do: It is not a specific fault but a generic warning. Have the car diagnosed with the right equipment to read the exact code before replacing any part.

1 documented fault that triggers it in the Audi

• Medium severity: Clogged particulate filter or faulty pressure sensor · 2.0 TDI engine · A3 II, A4 B8, Q3 I and 1 more

• Pollution control faulty: general guide

Seatbelt fault warning light or message

Urgency: Garage soon

The dashboard shows a warning related to the seatbelt or its pretensioner, separate from the generic "fasten your seatbelt" reminder. It may be caused by a fault in the sensor, the pyrotechnic pretensioner or the control unit that manages them.

What to do: Ask for the seatbelt and pretensioner system to be checked at a garage with the right diagnostic equipment, and check whether any manufacturer campaign is outstanding for your vehicle.

1 documented fault that triggers it in the Audi

• High severity: Faulty seatbelts (174 cars) · outside the engine · A3 IV

• Seatbelt warning: general guide