VW Taigo Engine Warning Hints at Knock Sensor Failure

Had nearly identical car problems with my 2018 VW T-Roc. The symptoms matched perfectly, poor performance, rough idle, decreased fuel efficiency and that persistent check engine light. The knock sensor connection was indeed the culprit. The wiring harness had developed a fault where it connects to the sensor. This caused intermittent signal issues which made the engine run rich as a protective measure. During inspection, the mechanic found corrosion in the connector pins. The fix required replacing both the wiring harness section and the knock sensor itself since the connection had degraded. It was a serious issue that needed immediate attention to prevent potential engine knock damage. Important points to have checked: Full diagnostic scan for knock sensor-related codes, Physical inspection of the wiring harness, Testing of the sensor signal under different RPM loads, Checking connector pins for corrosion, Verifying proper sensor mounting torque Getting this fixed properly resolved all the symptoms. The engine returned to smooth operation with normal fuel consumption. Would suggest having these specific areas examined rather than accepting a general diagnosis.

Thanks for the detailed reply. Your auto repair experience sounds just like what I am dealing with. Good to know the knock sensor was the root cause in your case. Really helpful breakdown of what the mechanic checked, will definitely ask for those diagnostic steps. My ignition timing was also off according to the scan, but the malfunction indicator keeps coming back even after adjustments. Would be curious to know roughly how much you ended up paying for the complete fix? Also wondering if you have had any recurring issues since the repair was done? I want to make sure I budget properly and get it fixed right the first time.

Glad I could help with your car problems. The knock sensor issue on my T-Roc was completely resolved after the repair, with no warning light or problems returning since. The repair bill came to 95€ for fixing the faulty cable connection to the sensor. The intermittent check engine light you mention despite timing adjustments strongly suggests a similar wiring issue. Once the proper connection was restored, my engine performance and fuel efficiency returned to normal levels. The key was having a thorough diagnostic scan that identified the exact nature of the connection fault. Having the wiring inspected and repaired properly the first time avoided more expensive repairs down the line. Make sure your mechanic checks the connector pins thoroughly for any signs of corrosion or damage. Poor connections can cause similar ignition timing issues that persist even after adjustments.

Thanks for the input. Finally got my Taigo looked at properly this week. The mechanic found exactly what was described, corroded connector pins on the knock sensor wiring. They did a full diagnostic scan which confirmed the ignition timing issues were related to the faulty connection. Total repair came to 120€ including new wiring harness section and labor. Been driving for a few days now and what a difference, no more check engine light, engine runs smoothly, and fuel consumption is back to normal. Poor performance issues completely gone. Really grateful for the advice about getting the wiring checked thoroughly. Saved me from possibly more expensive repairs if left unfixed. The diagnostic steps suggested helped ensure the mechanic found the root cause rather than just treating symptoms.