Temperature Safety Switch (Multi Function Temperature Sensor)

Temperature Sensor (Overheat Sensor - Multi Function):

There is no test procedure for this device, however there are distinct noticeable symptoms when it has failed. These symptoms are:

1. Engine temperature gauge becomes inoperative.
2. No boost pressure from turbocharger (wastegate frequency valve signal at 0% duty cycle) even though engine is NOT overheated.
3. Climate control shuts off (no A/C for no apparent reason) even though system is fully charged and engine is NOT overheated.

This device, affectionately referred to by many Audi trained mechanics as the "multi-malfunction sensor", is reported to have a particularly high mortality rate. If the engine control system has a problem that seems to be related to an overheated engine, yet the engine is not overheating, replace this sensor.