Aircon not working

[dean warren]

Hi all, my Dad has an A6 2007 2.0l tdi 140bhp BRE engine code (i think)
anyway the aircon hasnt really worked this year, so i plugged it into VCDS and was suprised to see no faults found on the aircon, it was showing pressure in the system. So thought it was just a re gassing. The auto button works but the fans dont come on in the enginebay, however they will come on when doing an output test with VCDS, I Took it in to be regassed today, and they confirmed there was very little refrigerant, 55g i think he said, and it should be over 500, but there are no leaks, but alass still no working aircon. After an hours drive tonight there was a very slight chill to the air, but still not enough to chill the cabin, and no fans on, with the bonnet open and engine running there seems like no click or rev change when i click between econ and auto, so i suspect the compressor has failed, but wouldnt this register a fault? Or am i barking up the wrong tree?

[B5NUT]

Unfortunately you are looking up the wrong tree, the aircon pump is a dumb bit if kit, it's a basic pump with a single wire going into it to activate the clutch on the compressor. If it's dead you won't get any fault codes and no aircon.

[gavin_tully]

Check the pulley first. Known to break up and just free wheel.
Does the pressure value change in VCDS when you switch Econ off. It should.

[dean warren]

Refrigerant circuit pressure remains 6.6bar on auto with econ on or off.


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[gavin_tully]

Take the cover off the front of the a/c pulley. I'd say it's sheared. Which it's designed to do in an overload condition. There only about £60. I've had to change 3 on 3 different family members A6's.

[TheFixer]

*Bandwagon* So I did the oil service on my 2007 A6 and when dropping the sump guard the pulley/clutch cover was lying on it. It has sheared off from the shaft,as designed. Can one point me to where I could get the pulley/clutch kit mentioned?

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[dean warren]

so an update on this, i have swapped the Pressure switch in the condenser and the quality switch under the rain tray. cleared the codes and within 20 seconds these come back.


Address 08: Auto HVAC Labels: 4F0-910-043.clb
Control Module Part Number: 4F0 910 043 HW: 4F2 820 043 N
Component and/or Version: KLIMABETAETIGUNGH20 0170
Software Coding: 0001302
Work Shop Code: WSC 02325 785 00200
VCID: 5BB5B4E29A03B89F39-800E
3 Faults Found:


00256 - A/C Pressure/Temperature Sensor (G395)
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


01858 - Air Outlet Sensor; Right Center (G348)
007 - Short to Ground
Freeze Frame:
Fault Status: 01100111
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


01592 - Air Quality Sensor (G238)
010 - Open or Short to Plus
Freeze Frame:
Fault Status: 01101010
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


Freeze Frame:
Temperature: 20.0°C
so im thinking a broken wire? but where
also my control panel and fans are working again.

[dean warren]

Also my pressure is showing as 90 PSI and in the red on my pressure gauge.

[rowdy-999]

so an update on this, i have swapped the Pressure switch in the condenser and the quality switch under the rain tray. cleared the codes and within 20 seconds these come back.


Address 08: Auto HVAC Labels: 4F0-910-043.clb
Control Module Part Number: 4F0 910 043 HW: 4F2 820 043 N
Component and/or Version: KLIMABETAETIGUNGH20 0170
Software Coding: 0001302
Work Shop Code: WSC 02325 785 00200
VCID: 5BB5B4E29A03B89F39-800E
3 Faults Found:


00256 - A/C Pressure/Temperature Sensor (G395)
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


01858 - Air Outlet Sensor; Right Center (G348)
007 - Short to Ground
Freeze Frame:
Fault Status: 01100111
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


01592 - Air Quality Sensor (G238)
010 - Open or Short to Plus
Freeze Frame:
Fault Status: 01101010
Fault Priority: 3
Fault Frequency: 1
Reset counter: 70
Mileage:
Time Indication: 0
Date: 2017.06.09
Time: 12:32:32


Freeze Frame:
Temperature: 20.0°C
so im thinking a broken wire? but where
also my control panel and fans are working again.

Didn't you say initially you had no AC fault codes?
Fans not working?....any engine codes related to this problem?

[dean warren]

Didn't you say initially you had no AC fault codes?
Fans not working?....any engine codes related to this problem?

Oh dam ive posted it on the wrong thread


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