Thanks again Steve. Completely checked the air box for IAT but found nothing so must be part of MAF. Fitted another brand new MAF today and the light came on with P0113 code error. Looked at the wiring but all looks good up to where it goes into the loom. Not sure where to go next but guess it needs Audi analysis and expertise (unkess my normal mechanic will look again).
One more question, the MAF has 4 wires in (see pic).
1: is blank.
2: has a reading of 12+volts. 3: nothing. 4: nothing.
5: 5.01v. My understanding is the PCM sends 5v to the IAT, which then reduces this dependent on temperature and, I assume, sends back the lower voltage via either lead 4 or 3? So any break/short in the wiring must be 3 or 4?
Thanks