I saw this tip on the D2 forum; it’s nice, quick and easy to do and only takes about 10 minutes from start to finish.
First thing to do is remove the engine acoustic cover (this article is relevant for a RHD Td5 UK spec vehicle) which involves removing a 15mm bolt on the driver’s side and two 13mm bolts on the passenger side, then lift clear. You’ll greeted with the view below, IAT sensor circled.
Next remove the two 8mm bolts holding the sensor itself, it should easily pull free. All you need to do now is clean the sensor, depending on how dirty it is it will either just need a quick wipe or if it’s really contaminated with oil you could use brake cleaner or something similar.
Once cleaned simply replace the sensor, then the acoustic cover and that’s it, done.
Cleaning the sensor helps to maintain optimum performance especially if you combine it with an intercooler flush and EGR removal, which is something I’ll be doing in the near future.