RS3 Cruise Control Failure With Stored Error Code

Faced exactly this on a 2020 S4 last month. The cruise control symptoms match, dashboard indicator but no engagement. The issue traced back to two potential root causes: 1. A faulty brake pedal switch, which the cruise control system monitors for safety 2. Damaged wiring between the speed sensor and control module In my case, diagnostic testing revealed corroded connections at the brake pedal switch. The speed sensor was functioning properly, but the system disabled cruise control due to inconsistent brake pedal switch signals. The fix required: Cleaning the brake pedal switch connectors, Replacing the actual pedal switch assembly, Clearing the stored fault codes This was not a serious mechanical issue, more of an electrical/sensor problem. The fuse box and main control modules were all working correctly. After the repair, the cruise control system restored full functionality. Worth checking these components first before replacing more expensive parts. A proper diagnostic scan should pinpoint if its the pedal switch or speed sensor causing the malfunction.

Thanks for sharing those details about the brake pedal switch repair. I had a similar cruise control failure on my RS3, but mine turned out to be related to the clock spring in the steering wheel. The steering wheel controls would work intermittently before the cruise control failed completely. The throttle position sensor was also showing some error codes, but replacing the clock spring resolved both issues. The car runs perfectly now with all cruise functions restored. Do you remember the total repair cost for your brake switch fix? Just wondering how it compares to what I paid. Also, has everything stayed working properly since the repair?

Good news. The brake pedal switch repair I had done cost 95 Euro total, which covered the cable repair and resolving a faulty plug connection. Much more reasonable than initially expected. The cruise control has worked flawlessly since the fix 3 weeks ago. Your clock spring issue is interesting, it shows how cruise control problems can stem from different components. While mine was related to the brake pedal switch sending incorrect signals, yours linked to the steering wheel electronics. Both cases prove these issues often trace back to electrical connections rather than major mechanical faults. The throttle position sensor error codes you mentioned commonly appear alongside cruise control faults since they share related circuitry. Once the root cause is found, whether its a blown fuse, faulty pedal switch, or clock spring, resolving it usually clears all related error codes.

Finally went to get it checked. The mechanic found that the speed sensor needed cleaning and recalibration. The whole repair including labor came to 180 Euro. Much better than the 800 Euro quote I got from another shop for a complete sensor replacement. The problem started after driving through heavy rain. Apparently water got into the connection, causing corrosion. The mechanic explained that speed sensors are sensitive to moisture and dirt buildup. After a thorough cleaning and testing the connections in the fuse box, everything works perfectly again. Really glad I asked here first and learned about the different potential causes. Saved me from unnecessarily replacing expensive parts. The cruise control now engages smoothly and maintains speed just like when the car was new. Good to know these issues usually have simple fixes rather than major mechanical problems.