NOx Sensor Alert: Passat Hybrid Exhaust Leak Fix Needed

As a Volkswagen Arteon eHybrid 2020 owner, I encountered similar nitrogen oxide sensor failure symptoms last month. The check engine light triggered due to a damaged wiring harness connecting to the NOx sensor, a common issue when the connector gets corroded or damaged from engine bay heat. The repair involved replacing both the wiring harness and the NOx sensor since the connection degradation had affected the sensor functionality. This is a serious repair that requires proper diagnostic equipment to ensure the air-fuel ratio stays optimal after component replacement. The exhaust leak you mentioned could be related, often a failing NOx sensor causes incorrect readings, leading the engine management system to adjust the fuel mixture incorrectly. This can create more strain on gaskets and exhaust components. The main steps for repair typically include: Full diagnostic scan, NOx sensor electrical testing, Exhaust system pressure test, Wiring harness inspection, Component replacement, System recalibration This repair should be handled by a certified hybrid vehicle technician, as proper diagnostic equipment and expertise with diesel engine emission systems is essential.

Thanks for sharing your experience with the NOx sensor issue. Your case sounds very similar to mine. Good point about the wiring harness, I should check that too. Could you share how much you ended up paying for the full repair? Also wondering if you had any other emission sensor or catalytic converter problems since getting it fixed? My pollution control warning light started flickering again yesterday, so trying to figure out if these issues tend to come back. Just for reference, my Passat hybrid shows 84000km now, so quite close to your mileage. The exhaust leak seems worse when the engine is cold.

Got good news to share about my NOx sensor repair. The issue turned out simpler than expected, just a faulty cable connection to the sensor. The mechanic found and fixed the connection problem for 95€, which was much less than expected for a nitrogen oxide sensor repair. Since the repair, all emission control systems have worked perfectly. No flickering warning lights or catalytic converter issues. The air-fuel ratio readings returned to normal, and the exhaust leak completely disappeared once the sensor was communicating properly again. Your cold engine symptoms match what I experienced before the fix. When the diesel engine starts cold, faulty sensor readings can cause the system to run rich until it warms up, which explains the worse exhaust smell. Based on my experience, get it checked soon. A simple connection issue can trigger multiple warnings, but leaving it unfixed risks damage to other emission components over time.

After reading about similar NOx sensor problems, I finally took my Passat to a certified hybrid technician last week. The diagnosis showed my nitrogen oxide sensor had indeed failed, mainly due to a corroded wiring connection. The mechanic also found a small crack in the exhaust manifold gasket causing the leak. Total repair costs came to 480€, covering: New NOx sensor, Wiring harness repair, Exhaust gasket replacement, Labor and diagnostic fees The catalytic converter and other emission sensors checked out fine. The air-fuel ratio is now properly regulated, and the exhaust leak is completely gone. No warning lights since the repair, even during cold starts. Really glad I got this fixed properly instead of trying cheaper alternatives. The certified technician explained everything clearly and showed me the damaged parts. Much better experience than my previous mechanic. Think I will stick with this workshop for future maintenance. Their expertise with hybrid emission systems was impressive.