A/C not blowing cold air

davc

davc

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My A/C hasn't been working for a while and as the weather is warming up I have decided to do something about it.

Address 08: Auto HVAC Labels: 8P0-820-043.lbl
Part No SW: 8P0 820 043 BH HW: 8P0 820 043 BH
Component: KlimavollautomatH09 0100
Revision: 000710 Serial number: 8P0820043BH
Shop #: WSC 00000 000 00000
VCID: 73E5D39712D0DC86965-8026

1 Fault Found:
01232 - A/C Compressor Regulator Valve (N280)
010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 2
Fault Frequency: 254
Reset counter: 73
Mileage: 42926 km
Time Indication: 0
Date: 2013.06.14
Time: 14:09:56

Freeze Frame:
Load: 50.0 %
Current: 0.000 A

From reading online it seems that the N280 valve is goosed and after hooking it up to VCDS today I saw only 6 bar of refrigerant pressure. According to VCDS the range should be from 2.6 to 29 bar. I don't know anything about A/C systems but if it's working I would expect the refrigerant pressure to rise as cooling is increased?

The other interesting thing is the Compressor Shutdown Code 19 (which isn't documented in VCDS). I have found 2 explanations online:

19 Compressor off (-Climatronic control unit -J255 was switched on via the "auxiliary heater" function.)
19 Compressor off (shutoff request from Vehicle Electrical System Control Module via CAN)



Address 08: Auto HVAC (8P0 820 043 BH)

15:45:59 Group 001: General
0.036 A A/C Regulating Valve (N280)
59.5 % A/C Regulating Valve (N280)
22.5 % High Pressure Sensor (G65)
6.0 bar Refrigerant Pressure

15:45:59 Group 002: Compressor Shut-Off Conditions
0.0 Current Shut-Off Condition
19.0 Last Shut-Off Condition
0.0 Last but One Shut-Off Condition
0.0 Last but Two Shut-Off Condition

15:45:59 Group 012
800 /min Engine Speed
0.0 km/h Vehicle Speed
0 Compress. Torque Signal Status
5.0 Nm Compressor Torque


Thursday,15,May,2014,15:52:38:26100
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.2.0
Data version: 20140212


Address 01: Engine (8P0 907 115 AB)

15:52:34 Group 050: Idle Speed Stabilization
820 /min Engine Speed (actual)
840 /min Engine Speed (specified)
A/C-High A/C Readiness
Compr.ON A/C Compressor

The car is going in on Sunday to get the system checked and re-gassed if necessary. If it turns out the N280 valve is the culprit I have found a company in the UK which can supply them. I'm just waiting for confirmation.

Any help in the meantime would be greatly appreciated.
 
davc said:
My A/C hasn't been working for a while and as the weather is warming up I have decided to do something about it.

Address 08: Auto HVAC Labels: 8P0-820-043.lbl
Part No SW: 8P0 820 043 BH HW: 8P0 820 043 BH
Component: KlimavollautomatH09 0100
Revision: 000710 Serial number: 8P0820043BH
Shop #: WSC 00000 000 00000
VCID: 73E5D39712D0DC86965-8026

1 Fault Found:
01232 - A/C Compressor Regulator Valve (N280)
010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 2
Fault Frequency: 254
Reset counter: 73
Mileage: 42926 km
Time Indication: 0
Date: 2013.06.14
Time: 14:09:56

Freeze Frame:
Load: 50.0 %
Current: 0.000 A

From reading online it seems that the N280 valve is goosed and after hooking it up to VCDS today I saw only 6 bar of refrigerant pressure. According to VCDS the range should be from 2.6 to 29 bar. I don't know anything about A/C systems but if it's working I would expect the refrigerant pressure to rise as cooling is increased?

The other interesting thing is the Compressor Shutdown Code 19 (which isn't documented in VCDS). I have found 2 explanations online:

19 Compressor off (-Climatronic control unit -J255 was switched on via the "auxiliary heater" function.)
19 Compressor off (shutoff request from Vehicle Electrical System Control Module via CAN)



Address 08: Auto HVAC (8P0 820 043 BH)

15:45:59 Group 001: General
0.036 A A/C Regulating Valve (N280)
59.5 % A/C Regulating Valve (N280)
22.5 % High Pressure Sensor (G65)
6.0 bar Refrigerant Pressure

15:45:59 Group 002: Compressor Shut-Off Conditions
0.0 Current Shut-Off Condition
19.0 Last Shut-Off Condition
0.0 Last but One Shut-Off Condition
0.0 Last but Two Shut-Off Condition

15:45:59 Group 012
800 /min Engine Speed
0.0 km/h Vehicle Speed
0 Compress. Torque Signal Status
5.0 Nm Compressor Torque


Thursday,15,May,2014,15:52:38:26100
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.2.0
Data version: 20140212


Address 01: Engine (8P0 907 115 AB)

15:52:34 Group 050: Idle Speed Stabilization
820 /min Engine Speed (actual)
840 /min Engine Speed (specified)
A/C-High A/C Readiness
Compr.ON A/C Compressor

The car is going in on Sunday to get the system checked and re-gassed if necessary. If it turns out the N280 valve is the culprit I have found a company in the UK which can supply them. I'm just waiting for confirmation.

Any help in the meantime would be greatly appreciated.
Click to expand...

6 bar pressure is an equalised pressure if your ac was not in operation at the time the n280 valve alters the displacement of the compressor ,should you have a high cabin temperature or full speed vent fan the valve will have the compressor fully loaded to bring the suction pressure down once the load is manageable the valve will decrease the compressor capacity.

as pressure and temperature are directly proportionate high pressure = high temp, low pressure = low temp
less heat load = lower pressure however the capacity control is in place to deal with load variations due to engine speed and thermal load.

when your system a/c is switched on the suction pressure (low side) will decrease and your discharge pressure (hp) will increase a good visual indication that is fully charged is the largest line (suction )will sweat (form condensation) on it right back from the evaporator to the compressor.
 
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Reactions: davc
I'd get the N280 changed before the regas as you'll likely need it done again after changing the valve
 
There is no charge if the re-gas doesn't fix the problem so I'll get the system evacuated before changing the valve.

If I go down the route of changing the compressor are there any parts I need other than the Receiver/Dryer and Expansion Valve?
 
You don't really need to change the expansion valve however the drier is recommended but you could likely get away without changing it providing the system is evacuated properly anything less than 2 torr is perfect
 
That's good to know, cheers again.

P.S I had to look up torr on wikipedia. Every day is a school day:)
 
Did you get the valve changed or the compressor? is it working now?

Can you pm the details of the company that can supply the valve please?

Cheers
 
Hello mate, I haven't had a chance to fix mine yet.

The company I used is Automotive Compressor Repairs Ltd - 01932 571980. If you ask for Craig he should be able to help you.
 
  • Like
Reactions: TechFreak
Thanks bud - I'll give them a bell ...

davc said:
Hello mate, I haven't had a chance to fix mine yet.

The company I used is Automotive Compressor Repairs Ltd - 01932 571980. If you ask for Craig he should be able to help you.
Click to expand...
 
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