Lexus GS NOx Sensor Failure

NOx sensor issues on the GS are pretty common. That said, are you sure it's the sensor itself and not something upstream causing the sensor to flag? An exhaust leak can definitely throw things off, potentially impacting the catalytic converter efficiency and triggering the NOx sensor error. Have you checked for any obvious damage to the exhaust system before the sensor?

Thanks for the quick reply. I visually inspected the exhaust system near the sensor and didn't notice any major cracks or holes, just some minor corrosion. Could a small leak really cause the NOx sensor to fail, or is it more likely the sensor connection as I initially suspected?

A small leak, especially close to the sensor, can indeed affect its readings. The sensor is extremely sensitive to changes in exhaust composition. However, given the stored error code and your suspicion of a faulty connection, it's difficult to say for sure without proper diagnostics. If the error code specifically points to an electrical issue with the sensor (e.g., open circuit, short to ground), the connection is the prime suspect. The best course of action would be to visit a workshop. It's also worth noting that even if it's just the connection, the sensor could have been damaged by the constant misreporting. Replacing this is a pollution control matter and should be handled professionally.

Thanks for confirming my suspicions about the connection and the potential for a small exhaust leak to cause issues. I followed your suggestion and took it to a local shop. They confirmed it was indeed the sensor connection. The cost was 95€. Appreciate the help!