RSQ3 Knock Sensor Repairs Cost Owners Big Money

Had the same knock sensor warning light issue on my 2018 RS3. The poor performance and high fuel consumption matched exactly what you describe. The root cause turned out to be a damaged wiring harness connecting the knock sensor to the ECU. The insulation had worn through, causing intermittent connection issues. The engine knock detection system was malfunctioning, making the ECU run rich fuel mixtures as a protective measure. This ended up being a serious issue requiring immediate attention since running without proper knock detection risks major engine damage. The repair involved replacing the entire knock sensor wiring harness and testing the sensor itself. The fix restored normal fuel efficiency and resolved the rough idle completely. Going to a certified shop was crucial since they had the proper diagnostic tools to pinpoint the exact failure point in the wiring. Would strongly recommend getting this checked soon, as driving with faulty knock detection can lead to expensive engine repairs if detonation occurs. The warning light and performance issues you describe are classic symptoms of this particular problem.

Thanks for sharing your experience. Your wiring harness diagnosis matches what my check engine light was indicating. Did the same repair route myself about 3 months ago for a similar knock sensor malfunction on my RSQ3. The car problems cleared up right after fixing the wiring. Just curious, do you remember what the total repair cost was for your case? Also wondering if youve had any other related issues pop up since the fix? My car seems to be running fine now but always good to know what to watch out for.

Thanks for asking about the repair costs. After getting the knock sensor issue fixed, the total came to 95 Euro for repairing the faulty cable connection. The warning light hasnt returned since, and fuel efficiency is back to normal levels. The auto repair was straightforward once the correct diagnosis was made. My car has been running perfectly for over a year now with no related problems. The check engine light has stayed off, and the rough idle completely disappeared after the fix. The key was addressing the issue promptly to prevent any potential engine damage. From my experience, once the wiring connection is properly repaired, these knock sensor problems rarely come back. Just keep an eye on your fuel consumption patterns, any sudden changes could indicate similar issues developing.

Got my car back from the shop yesterday after dealing with the knock sensor problem. The mechanic found the same wiring harness issue you mentioned. Total repair cost came to 120 Euro which seems reasonable compared to your experience. The check engine light is finally off and the rough idle is completely gone. Noticed an immediate improvement in fuel efficiency on the drive home. The engine feels much smoother now, especially at low speeds. Really glad I caught this early before it could cause more serious engine problems. The shop also did a full diagnostic scan which showed no other issues, so feeling confident about the repair. Thanks again for helping me avoid getting overcharged on this auto repair job.