Warning lights of the Audi A6: what each light means
In the 4 generations of the Audi A6, the documented faults light up 4 warning lights on the dashboard. The most frequent: engine warning light (6 faults), overheating (2 faults) and oil warning light (1 fault). Overheating and oil warning light call for stopping as soon as possible.
Which warning lights the faults of the Audi A6 trigger
Red ones first, and those that call for stopping. Below each warning light, the documented faults that trigger it, with their pages.
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.
2 documented faults that trigger it in the Audi A6
- High severity: Failing water pump and cooling system leaks · 3.0 TDI V6 engine · C6, C7 and C8
- Medium severity: Leak at the thermostat housing and water pump · Audi 3.0 TFSI V6 engine · C6 and C7
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.
1 documented fault that triggers it in the Audi A6
- Critical severity: Oil pump failure on the pumpe-düse 2.0 TDI · 2.0 TDI engine · C6
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.
1 documented fault that triggers it in the Audi A6
- Critical severity: Faulty dashboard that may prevent the front passenger airbag from deploying in the Audi A6 · outside the engine · C8
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.
6 documented faults that trigger it in the Audi A6
- Medium severity: EGR valve clogged with carbon · 1.9 TDI engine · C5
- High severity: Injector wear (needle seat) and injection faults · 3.0 TDI V6 engine · C6, C7 and C8
- High severity: Turbo with seized vanes or premature failure · 2.0 TDI engine · C6
- High severity: Timing chain stretch and tensioner wear · Audi 3.0 TFSI V6 engine · C7
- Medium severity: Worn intake flaps (swirl) and intake manifold · 3.0 TDI V6 engine · C6
- Low severity: PCV valve failure (crankcase ventilation) · Audi 3.0 TFSI V6 engine · C6 and C7
Frequently asked questions
Which warning lights come on most in the Audi A6?
Engine warning light: 6 documented faults, such as EGR valve clogged with carbon. Overheating: 2 documented faults, such as failing water pump and cooling system leaks. Oil warning light: 1 documented fault, such as oil pump failure on the pumpe-düse 2.0 TDI.
Which warning light of the Audi A6 is the most serious?
Overheating and oil warning light: its urgency is “as soon as possible”. Stop the car as soon as it is safe; on each warning light's page, at the top, you will find what to do.
Which generation of the Audi A6 has the most faults that trigger warning lights?
Audi A6 C6 (7 faults), Audi A6 C7 (5 faults), Audi A6 C8 (3 faults) and Audi A6 C5 (1 fault).
A warning light has come on in the Audi A6: what should I do?
Find which warning light it is on this page and check its urgency. With overheating and oil warning light, stop as soon as possible somewhere safe. For the others, book an appointment at a garage and have them read the fault code with an OBD reader: it shows which system has failed.