VW Atlas Power Loss Points to Faulty Exhaust Sensor

As a VW owner with some experience working on these cars, I had a similar issue with my 2018 VW Tiguan. The symptoms you describe match exactly what I experienced, poor performance, increased fuel consumption, and that dreaded check engine light. After taking it to my workshop, they diagnosed a leak in the exhaust system near the temperature sensor, which was causing incorrect readings to the engine management system. The complete fix included replacing both the faulty exhaust sensor and repairing the leak, totaling 265€. The repair resolved all symptoms completely, power returned to normal, fuel economy improved, and the check engine light disappeared. The workshop also did a thorough inspection of all exhaust components while they had it up on the lift, which I definitely recommend. Before suggesting more specific advice, could you share: Current mileage on your Atlas, Whether you notice any unusual exhaust sounds, If the check engine light is solid or flashing, Any specific error codes if you had them scanned This information would help determine if your issue matches what I experienced with my Tiguan, as these VW models often share similar exhaust system designs.

Last service done at 92000km. The workshop scanned the codes yesterday and found P0128 and P0113. This makes sense since the engine never seems to reach normal operating temperature according to the gauge. I can confirm there are no unusual exhaust sounds. The check engine light stays solid, not flashing. The exhaust sensor and surrounding exhaust system components look visually fine from what I can see, but the engine management system is clearly getting incorrect temperature readings. I worry this might damage the catalytic converter if left unfixed. Would getting just the temperature sensor replaced be enough, or should the whole heat sensor assembly be changed? The local parts supplier quoted 180€ for the OEM sensor alone.

Thanks for those details. Your situation sounds very similar to what I dealt with on my Tiguan. Those error codes combined with the temperature gauge behavior definitely point to temperature sensor issues affecting the engine management system. In my case, just replacing the sensor alone wasnt enough. While the parts supplier also quoted me just the sensor initially, the workshop found the entire temperature sensor assembly had deteriorated. The wiring and connector had heat damage that wasnt visible during basic inspection. I ended up needing the complete sensor assembly replaced to properly resolve the temperature fluctuation issues. The full assembly was around 320€ in parts, but it was worth it to prevent future problems. The engine management system now gets accurate readings and the catalytic converter is protected from potential damage from running too rich. From your description and my experience with nearly identical symptoms, I strongly recommend: Replace the complete sensor assembly, not just the sensor, Have the workshop check all surrounding exhaust system connections, Get the engine management system recalibrated after installation The higher upfront cost of the complete assembly saved me from having to do the job twice. My engine has been running perfectly since the repair, with normal operating temperatures and fuel consumption back to standard levels.

Thanks everyone for the helpful feedback. After weighing the advice, I decided to go ahead and replace the entire temperature sensor assembly rather than just the sensor. Better to do it right the first time and protect the catalytic converter and exhaust system from damage. The workshop confirmed they can check all the surrounding exhaust components during the repair. At 320€ for the complete assembly, the cost is higher than I initially planned, but it makes sense given the potential issues that could arise from a partial fix. I will post an update once the repair is complete to let others know if it resolved the temperature fluctuation, poor performance and fuel consumption problems. Really appreciate the detailed insights shared here, especially about checking the wiring and connections around the sensor assembly. This forum has been invaluable for making an informed repair decision. Just need to schedule the appointment now and hope they can fit me in soon before any additional engine management system issues develop. Thanks again for helping me avoid doing this repair twice.