VW Scirocco Knock Sensor Issues Draining Fuel Fast

I experienced similar car problems with my 2011 VW Golf TDI. The symptoms matched exactly, increased fuel consumption, rough idle, and malfunction indicator light. The knock sensor connection was indeed the culprit, but the issue was more complex than initially thought. The wiring harness to the knock sensor had deteriorated, causing intermittent signal issues affecting ignition timing. Auto repair required removing part of the intake manifold to access the connection point. The repair involved replacing the entire wiring harness section and testing the knock sensor functionality. This is a serious issue since incorrect knock sensor readings can lead to engine damage if left unattended. Most modern diesel engines rely heavily on precise knock sensor data to optimize performance and prevent detonation. The repair took about 4 hours at the shop. Critical diagnostic steps included: Testing sensor resistance values, Checking ground connections, Verifying ECU signal reception, Clearing fault codes, Test driving to confirm proper operation Post-repair, fuel consumption returned to normal and the rough idle completely disappeared. Regular maintenance checks of sensor connections can prevent similar issues.

Thanks for sharing your experience. I had nearly identical symptoms on my Scirocco last year, poor performance, warning light, the works. Really glad to hear your repair resolved the issue completely. Would you mind sharing what the total repair cost was for your knock sensor fix? Mine ended up being relatively expensive because they found some additional wiring issues while doing the work. Just curious how the costs compare. Also wondering if youve had any recurring problems since the repair? My car has been running smoothly for about 8 months now, but I keep a close eye on the fuel consumption just in case.

Just wanted to update on the repair costs since you asked. The fix for my knock sensor issue turned out to be quite straightforward, just 95€ to repair a faulty cable connection. Much more reasonable than initially expected. After getting it sorted by the mechanic, the auto repair has proven completely effective. The malfunction indicator light hasnt returned, and fuel efficiency is back to normal levels. No recurring issues whatsoever in the 14 months since the fix. The key was finding a mechanic who properly diagnosed the actual problem, a defective connection rather than a complete sensor failure. This saved significant costs compared to replacing the entire knock sensor unit. The car runs perfectly now, with steady idle and proper fuel consumption. Regular maintenance checks show everything working as it should. Really glad I got it addressed when I did to prevent potential engine damage. While keeping an eye on performance is always smart, you probably dont need to worry too much about the issue returning if it was properly repaired. The warning light will alert you if any problems develop.

Thanks everyone for the helpful replies. Just wanted to close the loop on my experience. Finally got my Scirocco fixed last week after finding a new mechanic who actually took the time to properly diagnose the issue. Turned out the wiring harness had some corrosion causing intermittent knock sensor readings. Total repair came to 180€ including parts and labor. More than I hoped but worth it to fix the fuel efficiency problems and rough running. The repair process was straightforward once they identified the real issue. They cleaned the connections, replaced the damaged section of the harness, and recalibrated the ignition timing. Engine knock is completely gone now and the car runs like new. Best part is my fuel consumption is back to normal levels. The whole experience taught me to trust my instincts when something feels off with the car and not to settle for incomplete diagnoses. No check engine light since the repair and the idle is perfectly smooth again. Really relieved to have this sorted properly after the frustrating first attempt at fixing it.