Please decipher diagnostic messages

[Annie]

Hi guys,

Can someone please interpret the following diagnostics faults for me

18043 - missing message from A/C control sporadic
17740 - sensor for NOX - G295 signal too large
17478 - NOX sensor heating contral signal
17446 - Heating activation sensor for NOX open

Does my NOX sensor need changing? or is it something to do with the AC/heating? I have read some old threads about NOX sensors, but I am still in the dark. I do not want to take the car to Audi until I have exhausted other cheaper avenues. The other big question is....................will it be costly? would appreciate any constructive input.

[Skipton01]

Hi Annie, the first error is very common and is nothing to worry about.

The other 3 relate to the NOX sensor, as you rightly thought. The cheapest option would be to have the part replaced, by an independant if possible, taking the part in with you.

If you call VAG Parts and ask them for a NOX sensor for your car, they will be the cheapest source.

Cheers,

Mike

[Annie]

Thanks very much for your prompt reply. Just needed confirmation to progress. I'm on the case as we speak.

Can I just add, when this problem arose the first place I thought of was this forum. If anyone knows of anyone that owns an A2 that is not part of this club......spread the word!!

cheers!

[Skipton01]

Thanks Annie - I'm always spreading the word and even my dealer helps out by telling other A2 owners!

Cheers,

Mike