Air Con - What to do

[BigEi]

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)

[Rob69]

Here's the function of G454, seems to be a loss of gas protection device. It looks like the system would have to be degassed to change it.
Read the note at the bottom - maybe you don't even have this sensor.


Function
The refrigerant temperature sender -G454 has an NTC sensor and records the temperature of the refrigerant within a measuring range from -20 °C to +150 °C. The normal operating range is +40 °C to +130 °C.

Signal usage
Based on the temperature signal and the pressure signal of the high-pressure sender -G65, the Climatronic control unit -J255 may detect an incipient loss of refrigerant such as may be caused by a defective seal. In this case the cooling function is disabled in order to protect the compressor.

Effect of failure
If there is no refrigerant temperature signal, an entry is made in the fault memory. Incipient refrigerant loss cannot be detected with a defective sensor. Consequently, in the event of a leak in the refrigerant circuit damage to the AC compressor is possible due to lack of lubrication.

Measured value block 003

Display zone 4

Measured value of refrigerant temperature sender -G454- in °C
On vehicles with 6-cylinder petrol engines the display zone is currently unoccupied (the refrigerant temperature sender -G454 is not fitted).

Resistance characteristic of refrigerant temperature sender -G454

Temperature Resistance value
-10 °C 9,000 kOhm
0 °C 5,000 kOhm
10 °C 3.500 kOhm
20 °C 2.500 kOhm
30 °C 1.750 kOhm
40 °C 1.200 kOhm
50 °C 0.800 kOhm

YZNote:
From 11.2007 the refrigerant temperature sender -G454 will be phased-out. On vehicles with a comfort air conditioner, ensure the correct Climatronic control unit -J255 is assigned. On vehicles with a 6-cylinder TDI engine or with an 8-cylinder engine without refrigerant temperature sender -G454, only a comfort version Climatronic control unit -J255 with part number 4L0 820 043 (from index K) may be fitted. If on vehicles with a basic air conditioner without refrigerant temperature sender -G454 the sender is indicated as a fault, perform the adaptions of the basic Climatronic control unit -J255. (Not necessary for comfort version air conditioners because of the different versions of Climatronic control unit -J255).

Adaption of Climatronic control unit -J255 (basic version, without refrigerant temperature sender -G454):
1. Adaption channel 32, adaption value 1
2. Adaption channel 24, adaption value 55
3. Adaption channel 25, adaption value 61

[BigEi]

Thank you, the Audi garage called to make sure I was happy with the service so I've relayed this item to them to consider.

[BigEi]

Here's the function of G454, seems to be a loss of gas protection device. It looks like the system would have to be degassed to change it.
Read the note at the bottom - maybe you don't even have this sensor.


Function
The refrigerant temperature sender -G454 has an NTC sensor and records the temperature of the refrigerant within a measuring range from -20 °C to +150 °C. The normal operating range is +40 °C to +130 °C.

Signal usage
Based on the temperature signal and the pressure signal of the high-pressure sender -G65, the Climatronic control unit -J255 may detect an incipient loss of refrigerant such as may be caused by a defective seal. In this case the cooling function is disabled in order to protect the compressor.

Effect of failure
If there is no refrigerant temperature signal, an entry is made in the fault memory. Incipient refrigerant loss cannot be detected with a defective sensor. Consequently, in the event of a leak in the refrigerant circuit damage to the AC compressor is possible due to lack of lubrication.

Measured value block 003

Display zone 4

Measured value of refrigerant temperature sender -G454- in °C
On vehicles with 6-cylinder petrol engines the display zone is currently unoccupied (the refrigerant temperature sender -G454 is not fitted).

Resistance characteristic of refrigerant temperature sender -G454

Temperature Resistance value
-10 °C 9,000 kOhm
0 °C 5,000 kOhm
10 °C 3.500 kOhm
20 °C 2.500 kOhm
30 °C 1.750 kOhm
40 °C 1.200 kOhm
50 °C 0.800 kOhm

YZNote:
From 11.2007 the refrigerant temperature sender -G454 will be phased-out. On vehicles with a comfort air conditioner, ensure the correct Climatronic control unit -J255 is assigned. On vehicles with a 6-cylinder TDI engine or with an 8-cylinder engine without refrigerant temperature sender -G454, only a comfort version Climatronic control unit -J255 with part number 4L0 820 043 (from index K) may be fitted. If on vehicles with a basic air conditioner without refrigerant temperature sender -G454 the sender is indicated as a fault, perform the adaptions of the basic Climatronic control unit -J255. (Not necessary for comfort version air conditioners because of the different versions of Climatronic control unit -J255).

Adaption of Climatronic control unit -J255 (basic version, without refrigerant temperature sender -G454):
1. Adaption channel 32, adaption value 1
2. Adaption channel 24, adaption value 55
3. Adaption channel 25, adaption value 61

Rob, may I ask where you got such detailed information from? I'd like to be able to purchase this resource as it's ideal for my needs.

Thanks
Ed

[Rob69]

Tinterweb bud!

[BigEi]

Thanks Rob,

I've now got ELSAWIN working and it's all I could need

[BigEi]

For anyone interested in this, using ELSAWIN, I've located the refrigerant sensor and I can see it easily, it's there and all plugged in.
I've spoken to the Audi garage and explained that they should have dealt with it when it was last in and they have agreed to collect the car, drop off a loan car for the day, diagnose the issue, replace the sensor if needed and not charge any labour or re-gas costs - which would be needed if the sensor is removed. I'm happy with this as I think they are at least trying, although would have been better if they had done a more thorough job the first time.

[Rob69]

Still - you've got the result you were looking for and getting the work done you've paid for. happy days!!

[Rob69]

BTW How are you using elsawin?

[BigEi]

Bought it on the internet for a few quid. Very useful indeed.