The rear O2 sensor, mounted in the rear of, or past the catalytic convertor, monitors the efficiency of the catalytic convertor by measuring the amount of oxygen in the exhaust flow. The heating element in the rear oxygen sensor can fail over time, causing a code for “internal resistance too high”.

It's easy to get a diagnosis wrong without the proper tools, so make sure you have a Ross-Tech VAG-COM (VCDS) Cable handy to take the guesswork out of the equation. Once you have diagnosed that the sensor has failed, replace it with this OEM unit for best results.

This O2 sensor is no longer available at VW, and has been superceded by part number 1K0998262Q.

The overall length of this sensor from is approximately 520mm.