So, when I got my Q7 4L the climate control wasn't working. I'm generally against main dealers but for this I decided to use them to get it fixed properly. Before taking it in, I got the codes read and it was reporting:
Temperature Sensor for Refrigerant (G454) switch/sensor

02508 - Temperature Sensor for Refrigerant (G454) 010 - Open or Short to Plus
Freeze Frame:
Fault Status: 01101010
Fault Priority: 3
Fault Frequency: 1
Reset counter: 7
Mileage: 253359 km
Time Indication: 0
Date: 2017.01.11 Time: 13:24:46
The Audi dealer had the car for 8 days for various jobs, the air cone being one. During this time they tracked down the problem to no gas as a result of a hole in the condensor. They fitted a new condensor, added gas and gave the air con system a full check over.
I collected the car yesterday and it is indeed blowing cold air and hot air when you change the temperature. An improvement and on the face of it fixed.

I connected by full version of VAGCOM up to the car this morning to check for any codes and noticed that it was still displaying: Temperature Sensor for Refrigerant (G454) switch/sensor.
I cleared the codes in case they had not erased the DTC's and sure enough it came straight back.

What should I do? The air con/climate control appears to be working fine from a user point of view and I had told Audi that the Climate control was not below cold air and even pointed them to the G454 error before they did the work.

What effect does an open/short temperature sensor have if the rest of the system is working?
Am I just worrying about something that is irrelevant
Should I be contacting Audi and saying they didn't fix the problem fully and they need to sort it, even though I know it will create more hassle.

It's not as if I scrimped on price, they effectively had a blank check to get the car sorted and 8 days is plenty long enough (they even had 1 month notice before it was booked in)