VW Transporter O2 Sensor Fix Impacts Fuel Economy

Had similar issues with a 2017 VW Tiguan when the oxygen sensor failed. The check engine light triggered alongside increased fuel consumption. A diagnostic scan confirmed the heater element in the O2 sensor stopped working properly. The exhaust system needed inspection since faulty sensors can indicate other underlying problems. In my case, the wiring harness connecting to the sensor was damaged, causing intermittent signal issues. The repair involved replacing both the sensor and damaged wiring. For oxygen sensor issues, a complete diagnostic check is important since they directly impact vehicle emissions and engine performance. While sensor replacement often resolves the problem, skipping the full system check risks missing related exhaust system damage. This type of repair requires proper equipment to test air-fuel mixture readings. Basic sensor swaps without verifying proper operation can lead to continued problems. The issue was serious enough to require immediate attention since poor readings can damage other engine components if left unchecked. Looking at your mileage, this is a common maintenance point for O2 sensor replacement, even without wiring problems. Consider requesting the technician check all sensor connections and related components while testing the new unit.

Thanks for sharing your experience. I have the exact same problem right now with my VW Transporter. The malfunction indicator came on last week and my mechanic also pointed to the oxygen sensor. Your detailed explanation really helps since I was unsure about getting the full system check. Would you mind sharing how much the repair cost in your case? Just wondering if other car components needed attention afterwards or if the check engine light stayed off once fixed?

The repair for my oxygen sensor heater issue ended up being straightforward and cost effective. The mechanic found a faulty cable connection to the sensor, which was fixed for 95€. No other car components needed replacement. After addressing the connection problem, the malfunction indicator turned off completely and never came back. The car regained its normal fuel efficiency, proving the oxygen sensor was working correctly again. The exhaust system check performed at the time showed everything else was functioning properly. Looking back, having the full diagnostic was worth it since it ruled out any deeper issues. A proper sensor testing procedure confirmed the repair worked as intended. This kind of focused repair saved money compared to blindly replacing parts. The oxygen sensor heater failure symptoms matched yours exactly, so hopefully your fix will be equally simple. Just make sure they verify proper sensor operation after the repair to prevent any recurring issues.

Update on my VW Transporter situation, took it to a new mechanic yesterday after reading your helpful feedback. They did a complete diagnostic and found the exact same issue, bad wiring to the O2 sensor plus the sensor itself was failing. Total repair came to 120€ including parts and labor. The mechanic showed me the damaged wiring and explained how it affected the air-fuel ratio readings. They did a full exhaust system check while at it, which thankfully showed everything else was fine. The check engine light turned off right after the repair and fuel consumption is back to normal. Really glad I went for the complete diagnostic rather than just swapping the sensor. The new shop did great work testing everything properly. Thanks again for steering me in the right direction with this!