Audi is recalling 1.27 million cars across the world, with A4, A5, A5 Cabriolet and Q5 models built between April 2011 and May 2015 affected.
The recall is due to the risk of a fire caused by "thermal overload occurring at the plug connectors of the electrical connections in the auxiliary heater due to friction corrosion", Audi states. Incorrect coatings on the contacts are also to blame.
The friction is caused by stress and movement in the components, which in turn can cause an electrical fire. The recall will fit a new auxiliary heating element with improved electrical contacts.
Audi advises owners that their cars can still be driven despite the fault, but if a burning smell can be detected, they should park the car and call their local Audi dealer.
Audi discovered the fault through product monitoring checks.
It’s not yet known how many UK cars are affected by the recall; 875,000 cars are affected in Europe, 250,000 in North America and 47,000 in Asia.