intake temp vauxhall 1.7 CDTI

Calculating the air/fuel mixture. The density of the air changes according to the temperature. It's the same reason why turbocharged engines often have intercoolers, or why a low-tech car might seem to run better on a cool, damp day than a hot one.

I would measure the actual resistance of the temp sender, it is not unknown for software to incorrectly report a reading.

Autodata does not seem to have the details for your exact model, but for the DTI it says that terminals 1 and 3 of the maf are the temp sender and at 0 degrees c they should read around 5120 ohms, at 10 deg.3384 at 20 2290, at

so if yours is showing almost continuity then it would give 60 degrees and be faulty, if it shows something near right on the ohmmeter then just ignore what the reader says.

I would measure the actual resistance of the temp sender, it is not unknown for software to incorrectly report a reading.

Autodata does not seem to have the details for your exact model, but for the DTI it says that terminals 1 and 3 of the maf are the temp sender and at 0 degrees c they should read around 5120 ohms, at 10 deg.3384 at 20 2290, at

so if yours is showing almost continuity then it would give 60 degrees and be faulty, if it shows something near right on the ohmmeter then just ignore what the reader says.

I have measured between one of the end terminals (they are not numbered) and the third in terminal and I get 495 ohms so it looks to be u/s. The MAF reading goes up and down with the revs and it runs and starts with no EML light on should I just leave it ?

it doesn't know anything is wrong, so no eml light. if the economy is ok and it seems to run ok, then I would leave it. As an experiment you could add a suitable resistor to simulate a suitable temperature and see if the software reads right and if it runs better (do a tankfull to get the actual economy). You could even add a variable resistor and tweak it to your heart's content !

the connector on the maf is numbered inside in the tiniest print iirc