VW Tiguan Check Engine Light Persists After Repair

I encountered similar issues with my 2011 VW Golf TSI. The check engine light persisted after initial repairs, and car diagnostics showed incomplete readiness monitors. The root cause was a combination of problems in the exhaust system and faulty oxygen sensors. The initial vehicle inspection missed these underlying issues. When I switched repair shops, they performed a complete OBD scan and found that the catalytic converter was underperforming, affecting multiple system readiness tests. They also discovered the speed sensor wiring had corroded, causing unreliable speedometer readings. The fix required: Replacing oxygen sensors, Cleaning throttle body, Repairing speed sensor wiring, Performing a specific drive cycle to reset readiness monitors After these repairs, the emissions test passed successfully and all readiness monitors completed their cycles. The speedometer now displays correctly and the check engine light remains off. Your symptoms strongly suggest similar underlying issues that need proper diagnosis. A complete car diagnostics scan from a VW specialist would be recommended, as generic OBD readers might not catch all manufacturer-specific codes.

Thanks for sharing that experience. Having the same car, I dealt with nearly identical problems last year. The readiness monitors kept showing incomplete and my check engine light would not clear even after basic repairs. Did you remember what the total repair cost came out to for fixing all those issues? My shop charged quite a bit for the oxygen sensors alone. Also wondering if youve had any recurring problems since the repairs? My speedometer occasionally still acts up in cold weather, but the emissions test readings have stayed good. Getting a second opinion from a VW specialist definitely sounds like the right call here, as my regular mechanic originally missed the connection between the sensors and catalytic converter performance.

Good news, after dealing with these exact sensor and readiness monitor issues last year, everything was resolved without any repair costs. The key was getting proper OBD readiness testing done at a specialized shop. They discovered the system just needed a complete drive cycle to reset all monitoring systems correctly. Since having that done, my check engine light has stayed off and all readiness tests complete normally. The original warning message cleared once the computer properly registered all sensor data. This was way better than replacing parts unnecessarily. For your speedometer concerns, cold weather sensitivity often points to wiring rather than sensor problems. A full diagnostic scan would help pinpoint if there are any remaining electrical issues affecting the speed readings. The drive cycle process that fixed my system readiness might help stabilize your readings too. The exhaust system and emissions have performed perfectly since the computer reset. Sometimes these monitoring systems just need a proper reset and drive cycle rather than expensive parts replacements. Having the right diagnostic equipment made all the difference in my case. Looking back, I would still recommend getting that VW specialist check as they have the proper tools to analyze these model-specific issues thoroughly. The complete OBD readiness reset they performed saved me from unnecessary repairs.

Had similar issues and finally decided to get a second opinion. Took my Tiguan to a different shop specializing in VWs. They immediately spotted the real problem, faulty connections between the oxygen sensors and computer system. Previous mechanic kept replacing parts without addressing the actual issue. The new shop did a full system readiness check and found the exhaust system was working fine, just not communicating properly with the onboard computer. They cleaned all sensor connections and performed a specific drive cycle to reset the monitoring systems. Vehicle inspection showed everything working normally after that. Total cost came to 450€ for diagnostic work and electrical repairs, way less than the 1200€ my old mechanic wanted for unnecessary parts. The check engine light has stayed off for 3 months now. Speedometer works perfectly and all readiness tests complete normally. Really glad I trusted my gut and got that second opinion. Next step is scheduling regular maintenance with the new shop. They clearly understand these VW-specific issues better. Sometimes finding the right mechanic makes all the difference in getting problems properly diagnosed and fixed the first time.