Mark X NOx Sensor Failure

Afternoon. My 2013 Toyota Mark X, gasoline engine, is throwing up some errors. Check engine light is on, and the diagnostic tool is showing a NOx sensor failure. I've also noticed what seems to be a slight exhaust leak. I've had a look at the sensor itself, and the cable and plug connection seem a bit suspect. Anyone else had similar issues?

4 comment(s)

Hello. I had a similar problem with my Mark X. The NOx sensor, or nitrogen oxide sensor, is part of the exhaust system and is essential for reducing emissions. It monitors the level of nitrogen oxides in the exhaust gas, which is especially important for diesel engines, but gasoline engines have it too. If the cable or plug connection of the emission sensor is defective, it will cause a leak. Did you check the sensor itself?

Thanks for the quick reply. I visually inspected the sensor, and it doesn't appear to be physically damaged. But how can I be certain that the sensor is faulty and not a deeper issue within the exhaust system or the catalytic converter, perhaps?

If the error memory reports an explicit NOx sensor failure, and you've confirmed a potential defect in the wiring, it's likely the sensor. I would advise taking your car to the workshop, as they will be able to say what's wrong and repair it.

Appreciate the insight. I'll get it booked into the shop. Turns out the cable was indeed faulty, like you said. New cable and fitting, and the error is gone. Cost me about 95€.

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