TSBs

Resolving Audi no start, hard pedal problem

March 24, 2025

This bulletin applies to 2017-2023 Audi Q7, 2017-2021 A4, 2018-2021 A5/S6/Q5/SQ5/RS5, 2019-2023 Q8, 2019-2021 A6/A7, 2020-2023 SQ7/SQ8/RSQ8 and 2021 RS5 Sportback, RS6 Avant, RS7, Q5 Sportback and SQ5 Sportback vehicles.

Mike Mavrigian

Related To:

Mitchell 1

Check the vacuum hose, sensor G608, connectors, seals and valves for possible damage. Check for leaks according to ELSA. Check for small cracks in the vacuum hose or in the connection points between check valves. Replace as needed.

After a short stationary period, the vehicle sporadically may not start and there is a hard brake pedal. When starting the engine, the usual brake force may not be enough to get the start authorization of the brake light switch.

Normally, a vacuum of 600 to 900 mbar is reached. Depending on the parking position (slope) or the user behavior, the vehicle is parked with a small vacuum. Within 12 hours, the vacuum may drop by up to 400 mbar.

Check the vacuum hose, sensor G608, connectors, seals and valves for possible damage. Check for leaks according to ELSA. Check for small cracks in the vacuum hose or in the connection points between check valves. Replace as needed.

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.