Service Repair

Audi Thermostat May Be Faulty

Dec. 30, 2020

This bulletin applies to 2017-2020 Audi A4, 2020 Q7, 2019-2020 Q8, and 2018-2020 A6/A7 vehicles. The MIL may be on and the fan may be running permanently.

Information courtesy of Mitchell 1,

Mike Mavrigian

This bulletin applies to 2017-2020 Audi A4, 2020 Q7, 2019-2020 Q8, and 2018-2020 A6/A7 vehicles. The MIL may be on and the fan may be running permanently.

At least two DTCs may be stored in the ECM, including P218100 (fault in cooling system), P017B00 (sensor for cylinder head temperature implausible signal), P308100 (engine temperature too low) and/or P01E400 (sender 3 for coolant temperature implausible signal).

Remove the thermostat and check whether it closes completely. If the coolant is still warm, put the thermostat in cold water to restore its original condition.

If there is a gap between the chamber and seal, the thermostat is faulty.

About the Author

Information courtesy of Mitchell 1

Information for Technical Service Bulletins comes from ProDemand, Mitchell 1's auto repair information software for domestic and import vehicles. Headquartered in San Diego, Mitchell 1 has provided quality repair information solutions to the automotive industry since 1918.

About the Author

Mike Mavrigian | Motor Age Editor

Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety of specialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.