The dash shows "Error: Workshop! Only leave vehicle in position P" with an audible warning. The message appears in whatever language the car is set to, for example "Fehler: Werkstatt! Fahrzeug nur in Stellung P verlassen" in German.

The message points at the gearbox, but the fault is not there. A tiny switch sits in the module under the selector lever and signals that the lever is in park (P). Its contact wears and can also burn. That makes the signal unreliable, and the car warns you. The fault codes appear as 617752, P173400 or B116229.

At first it is intermittent. Sometimes the message comes up, sometimes not, so a short test drive easily misses it. Later it becomes permanent, and the gearbox can drop into limp mode.

This fault looks more expensive than it is. The maker released a separate retrofit switch kit for it (5Q0713128A for the black module, 3Q0713128 for the white one), which can be fitted in half an hour. The kit costs 70 to 100 pounds. At a franchised dealer, however, the whole selector lever module sometimes gets replaced, which costs 626 to 1,000 pounds there. So the difference between the two routes is roughly tenfold.

The affected group is post 2013 MQB platform Volkswagen, Audi, Seat and Skoda cars with a DSG gearbox. The switch is in these gearboxes, because that is what these cars have in common. The part itself is not part of the gearbox but of the module under the lever.