simonsky7

G Klasse NOx Sensor and Exhaust Leak

My 2011 Mercedes G Klasse with a gasoline engine is showing a NOx sensor failure at 228115 km. The check engine light is on, and there's an error code. I'm also detecting an exhaust leak. It looks like the cable or plug connection might be the problem. Could this be it before I replace the sensor? Repair is about 95€.

4 comment(s)

A NOx sensor failure and exhaust leak on a G Klasse is tricky. The cable/plug connection could be it, but be careful before you decide. With the age and mileage, is the exhaust system okay? Corrosion could look like sensor failure. Did you check the sensor's wiring for damage besides the connection?

The exhaust looks good, no rust or damage near the sensor. The wiring looks fine too. Could a bad emission sensor cause both the NOx sensor error and the exhaust leak? Maybe the leak is small and hard to find without special tools?

A bad emission sensor affecting NOx readings is possible, but the exhaust leak is odd. If the visual check and wiring are good, the sensor is likely bad. But, to be sure, take it to a shop with smoke testing gear. They can find the leak and check the sensor under load. It might save money later.

Got it. I'll take the G Klasse for a smoke test and NOx sensor check. Turns out the cable was bad. It's running well now.

Join the discussion now: