VW Taigo O2 Sensor Issues Causing High Fuel Usage

I had a very similar issue with my 2020 VW T-Cross. As someone with some experience working on VWs, I first noticed the check engine light and increased fuel consumption, which immediately made me think of sensor issues. My workshop ran diagnostics and found that the oxygen sensor wasnt the problem itself, it turned out to be a loose connection at the O2 sensor plug. The exhaust sensor readings were erratic because of this faulty connection, causing the air-fuel ratio to be consistently off. The fix was pretty straightforward. The mechanic cleaned the connector, secured it properly, and reset the check engine light. Total cost was 95€ for diagnostic and repair work. Since then, fuel consumption returned to normal and the engine runs perfectly. What engine size does your Taigo have? Also, when did you first notice the increased fuel consumption? This information would help determine if your situation matches what I experienced. Has the check engine light been constant or intermittent? The issue could be different on your specific model, but based on the symptoms, having a professional check the sensor connections would be a good starting point.

Last service was done at 80000km and all seemed fine then. The increased fuel consumption started about 2 weeks ago, and I am seeing roughly 1.5L more per 100km compared to before. The check engine light has been constant since it first appeared. After reading about oxygen sensor symptoms and getting your feedback, I am more convinced the O2 sensor could be the culprit. The automotive sensor connections were checked already and seem secure, so I suspect the catalytic converter or sensor itself might need replacement. Before committing to expensive car maintenance, I will get a second opinion from another workshop that specializes in VW sensor diagnostics. Will keep the forum updated on what they find.

Thanks for the update on your Taigo situation. Based on what you describe, your symptoms do sound more serious than my connector issue, especially since the connections were already checked. In my case, after the initial connector fix didnt solve it, we discovered the oxygen sensor itself had degraded, a common issue that affects the exhaust system over time. The replacement automotive sensor cost 180€ plus labor. What helped confirm the diagnosis was the consistent fuel consumption increase you mentioned, 1.5L/100km matches almost exactly what I experienced. The steady check engine light is another typical indicator of sensor failure rather than an intermittent connection problem. One suggestion: have them check if the catalytic converter is still working properly. A faulty oxygen sensor can sometimes damage the cat over time by running the mixture too rich. In my case we caught it early enough that the catalytic converter was fine. Good call on getting that second opinion. When the workshop does the diagnostic, ask them to check both upstream and downstream oxygen sensors, as either one can cause these symptoms.

Thanks for the detailed info about your connector issue. Mine is a 1.0L TSI engine, and I first noticed the higher fuel consumption about 2 weeks ago. The check engine light has been constant, not flickering or intermittent. The increased fuel efficiency problems started around 80000km, right after the last service when everything seemed fine. Currently using about 1.5L more per 100km compared to normal, which matches what you experienced. The oxygen sensor connections were already checked and are secure, so I suspect either the catalytic converter or the sensor itself might need replacement. The steady check engine light and consistent high fuel consumption really point toward sensor failure rather than a loose connection. Before moving forward with potentially expensive repairs, I will get a second opinion from a workshop that specializes in VW exhaust sensor diagnostics. Will update the forum once I know more about what they find during testing. Thanks for sharing your repair experience, it helps confirm I am on the right track investigating the sensor system.