Golf Mk5 1.6 Engine Error Codes

[Challo]

A friend has a Mk5 1.6 FSI 2006 Golf which is throwing up some engine management codes which are P2096 and P2202 and seem to relate to the NOX Sensor potentially failing. On google it seems that people have had the same codes but its been due to exhuast leaks, air intake issues etc.

Although im going to suggest getting the sensor changed, is there anything he can check before? I know he hasn't always got the car serviced regulary in terms of filters (air/fuel) so could this potentially clear the issue?

Thanks