Multiple Audi A3 Electronics Failures, Fix Discussion

Had a similar situation with my 2002 Audi A4, so I have some experience with these electronics issues. Sounds very familiar to the problems I faced. The root cause in my case was a faulty cable connection near the steering wheel, affecting multiple car electronics systems simultaneously. The diagnostics showed several error codes related to the speedometer sensor and cruise control module. My workshop found that the wiring harness connecting to the steering wheel controls had deteriorated, causing intermittent connectivity issues. They had to partially disassemble the steering wheel assembly to access and repair the connections. The total repair cost was 95 Euro, and they completed the work in about 2 hours. Before you proceed with repairs, could you share: Have you checked the fuse box for any blown fuses? Are there any other warning lights on the dashboard? Can you share the specific fault codes from the diagnostics? Does the throttle body respond normally when accelerating? This information would help determine if your issue matches what I experienced and could save you time and money in diagnosing the problem.

Last service done at 108859 KM The fault codes point to issues with both the throttle body actuator and cruise control module. My mechanic suggested starting with basic troubleshooting. Fuses are all intact and the only warning light is the speedometer error. When accelerating, there is a slight delay in throttle response. Just wondering whether changing just the throttle body actuator would resolve all these malfunctions, since they seem interconnected? Want to avoid replacing parts unnecessarily if one component is causing cascade failures in the system.

Thanks for providing those details about your A3. After dealing with similar car electronics issues in my A4, I can share some relevant insights. When I encountered that delayed throttle response along with cruise control malfunction, replacing just the throttle body actuator did fix all the interconnected problems. The throttle body serves as a central component that affects multiple systems, including cruise control and speed sensing. The repair on my A4 cost 320 Euro for the part plus labor. Once replaced, all the error codes cleared and the speedometer returned to normal operation. The non-functional cruise control also started working perfectly again. Key points from my experience: Combined symptoms often trace back to the throttle body, A faulty throttle body can trigger multiple error codes, The delayed response you describe matches the classic symptoms, Replacing this single part resolved the cascade of malfunctions Would recommend having your mechanic verify the throttle body electrical connections first, as sometimes cleaning the contacts can resolve these issues without full replacement.

Thanks for sharing those experiences. After reviewing all the responses and comparing them to my A3's symptoms, I think I'll move forward with checking the throttle body actuator first. The diagnostic patterns seem very similar, especially the connection between the speedometer error and cruise control malfunction. I really appreciate the cost estimate of 320 Euro, helps me budget for the repair. My mechanic can probably verify the electrical connections during the initial inspection to rule out simpler fixes before replacing the entire actuator. Good to know this approach worked for other Audi owners experiencing similar car electronics issues. I'll schedule the diagnostics next week and ask them to specifically examine the throttle body connections before proceeding with any parts replacement. Will hold off on exploring other potential fixes until we see if this resolves the cascade of malfunctions in the system.