VW Taigo O2 Sensor Issues Impact Fuel Consumption

I faced a similar issue with my 2020 VW T-Cross. As someone with some hands-on experience working on VWs, I can share what worked in my case. The check engine light came on along with increased fuel consumption. The diagnostic scan pointed to a faulty sensor, specifically the oxygen sensor heater element. The root cause turned out to be a damaged cable connection to the sensor, which was causing erratic readings and affecting vehicle emissions. After taking it to my regular workshop, they performed: Complete diagnostic testing to confirm the malfunction indicator was indeed triggered by the O2 sensor, Visual inspection of the wiring harness, Testing of the sensor circuit The repair involved replacing the damaged wiring connector and ensuring proper connection to the sensor. Total cost was 95€ including diagnostic work. To help troubleshoot your case more effectively, could you share: Current mileage on your Taigo, When you first noticed the increased fuel consumption, Any other symptoms besides the check engine light, Whether you notice any exhaust smell or unusual engine behavior This would help determine if your issue is similar to what I experienced or if there might be other factors involved.

I have 111149km on the clock since my last service. The wiring diagnosis makes sense, I noticed the fuel consumption increase about 2 weeks before the check engine light appeared. No unusual exhaust smells, but the engine seems to run slightly rougher at idle. The malfunction indicator stays on consistently now. Based on your experience, I will have my mechanic thoroughly check the wiring harness and sensor connections before replacing any parts. A faulty sensor can definitely cause these symptoms, but ruling out wiring issues first could save unnecessary parts replacement. Thanks for sharing those specific troubleshooting steps. The oxygen sensor circuit testing will be particularly helpful to determine the root cause.

Thanks for the additional details about your Taigo. Those symptoms align closely with what I experienced on my T-Cross, especially the rough idle developing after the initial fuel consumption increase. In my case, the wiring issue was causing the heater element in the oxygen sensor to work intermittently, which explained the gradual decline in performance before the malfunction indicator stayed on permanently. The sensor testing revealed voltage fluctuations that pointed directly to the connection problem. With your mileage being over 110000km, its worth having your mechanic check both the wiring and the sensor itself. Car components like oxygen sensors typically last 80000-120000km, so you might be approaching the normal replacement interval anyway. A quick tip from my repair experience: my mechanic found that gently flexing the wiring harness while monitoring the sensor readings helped pinpoint the exact location of the connection fault. This saved time in the diagnostic process and helped confirm the repair was successful. Let us know what your mechanic finds. Your systematic approach to troubleshooting should help avoid unnecessary parts replacement.

I understand that on my vehicle, the rough idle combined with fuel consumption issues started before the check engine light, which really does point toward an oxygen sensor or wiring problem. The mileage timing makes sense too, at 111149km the sensor could be naturally wearing out. After reviewing the wiring diagnostic approach suggested, I scheduled an appointment with my mechanic for next week. Knowing now about testing the harness while flexing it and monitoring voltage readings will help ensure we identify whether its truly a faulty sensor or just a connection issue. I will also have them check the air-fuel ratio readings during diagnosis since that seems to be another indicator of sensor performance. The systematic troubleshooting approach focusing on both wiring and sensor testing should help avoid replacing car components unnecessarily. Really appreciate the detailed insight about your similar repair experience. I will update the forum once my mechanic completes the diagnostic work and we know whether it was a wiring or sensor issue.