Audi S3 Cruise Control Failure & Display Error Fix Help

Having some experience with car electronics, I encountered a similar issue on my Audi A3 1998. The symptoms were nearly identical, with the cruise control becoming non-functional and error messages appearing in the display. After investigating, it turned out to be a loose cable connection near the throttle body. The workshop found that moisture had caused corrosion on one of the plug connections, leading to intermittent malfunctions in the system. The repair involved cleaning the connections and replacing a damaged wiring section. Total cost was 95 Euro including diagnostics. Since the fix, the system has worked flawlessly. Before jumping to conclusions, could you share: Are there any other electrical issues? What specific error codes are stored? Does the malfunction occur more frequently in wet conditions? Have you checked the fuse box for any obvious issues? This could help pinpoint whether you are dealing with a similar connection problem or if there might be other underlying issues with your S3. Try checking the fuses first, its a simple and free first step. If everything looks good there, you might need professional diagnostics to identify the exact cause.

Thanks for troubleshooting suggestions. Last service done at 189000 KM. I checked all fuses in the box and they seem fine. The malfunction really only started showing up in dry conditions, which makes me think its not moisture related in my case. The error codes are showing throttle body communication issues, specifically P1571 and P1545. No other electrical problems noticed so far. Has anyone else experienced these specific error codes? Really hoping to avoid a complete throttle body replacement if possible.

Having resolved the same issue with my Audi A3, I can now confirm that error codes P1571 and P1545 usually point to communication problems with the throttle body control module rather than a complete failure of the unit itself. Since you mentioned the issue occurs in dry conditions and all fuses check out, this likely rules out my initial moisture-related diagnosis. In my follow-up research, I learned that the throttle body control module can develop intermittent communication issues due to carbon buildup or worn electrical contacts. Before replacing the entire throttle body, consider these steps that might resolve the faulty system: 1. Clean the throttle body thoroughly with proper throttle body cleaner 2. Check and clean all electrical connections to the control module 3. Run a complete diagnostics scan to verify if the steering wheel controls are also affected The good news is that in many cases, a thorough cleaning and connection check resolves these cruise control issues without major parts replacement. Professional cleaning service typically costs around 80 Euro, significantly less than a new throttle body. If cleaning doesnt resolve it, then throttle body replacement might be necessary, but start with the less expensive option first.

Thanks for the detailed response. I will definitely try cleaning the throttle body and connections first since its much cheaper than replacing parts. Just checked the electrical connections and there is some visible residue around the actuator contacts, so that could be causing the non-functional cruise control. Will get the proper cleaner and give it a try this weekend. The diagnostics you suggested about checking the steering wheel controls is a good point, I noticed the buttons feel a bit less responsive lately which might be related. If cleaning doesnt solve the faulty system issues, I will take it to a shop for professional diagnostics before replacing any major components. I will update once I try the cleaning. Really hoping to avoid the full throttle body replacement cost. The error codes seem to match what others have experienced with similar communication problems.