Hi,
having recieved my new nanocom I saw that the IAT Sensor shows a temperature that is about 15-20 Degrees C below the actual temperature.
Wiring ist OK, 5V coming from the ECU and the Ohm reading is about what is to be expected accordin to a table that circulating the internet.
Since the Sensor does not seem to be available anywhere I would like to find out why the treading is off.
I could:

• measure it at different temperatures (outside/inside/hairdryer) and see what the readings say
• measure at the ECU connectors if the wiring to/from the sensor is OK (voltage and resistance same as at sensor connector)
  Ideas ?
  thanks and greetings,
  Max.

They always read low but it is irrelevant. It only does anything if the intake temperature rises above 55C. Mine usually reads around -5C when the ambient is 10C. Even if it is disconnected it will flag an error code but have no affect.

Oh great, thank you ! Quick fix !
So I can cross this from my mental P38-woes list :-D

A few years back I did a loom extension to the IAT with extra resistors so that the ECM sees a raised intake temperature (I had time on my hands, at that point). Pretty sure it makes zero difference, as Richard says

I had the Nanocom plugged into mine yesterday and the IAT was showing -1C when the HEVAC was showing an external temperature of 12C, so 13 degrees difference. I was taking readings to compare with the 4.0SE as that is still running like a dog on petrol (but perfectly on LPG). The 4.0SE was parked in the sun so showing 14C external and the IAT was showing 1C, so the same 13 degrees difference.

Not checked mine in ages. Will have a look in the morning if I remember.