Air conditioning is not working

[S11KA]

Hello everyone! I’m new in your forum. I’d like to ask you if you have any idea what’s wrong with my air conditioning in Audi A4 2004 (B6). It's not blowing cold air at all. The AC has just filled with refrigenerant but the problem still exists. There are no fault codes and the adaptation in VCDS is fine. No problems with the econ light either.

According to Measuring Value Blocks(MVBs) it seems for me that the compressor is running normally (Group 002: Last Compressor Shut-Off Criteria). Any idea what could cause the problem?

Below the information of MVBs. Thank you in advance!



Thursday,05,May,2016,10:07:39:62939
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: Release 12.12.0 (x64)
Data version: 20130910




Address 08: Auto HVAC (8E0 820 043 AB)

10:07:26 Group 001
0.648 A A/C Valve (N280) Current
64.0 % A/C Valve (N280) Duty Cycle
22.5 % High-Pressure Signal (G65)
6.0 bar Refrigerant Circuit Pressure

10:07:26 Group 002: Last Compressor Shut-Off Criteria
0.0 Current Criteria
0.0 Last Criteria
0.0 Last but one Criteria
0.0 Last but two Criteria

10:07:26 Group 003: Left Temperature Flap Control Motor (V158)
22.0 Current Value
19.0 Specified Value
22.0 Minimum Position (Cooling)
229.0 Maximum Position (Heating)

10:08:10 Group 004: Right Temperature Flap Control Motor (V159)
22.0 Current Value
19.0 Specified Value
22.0 Minimum Position (Cooling)
230.0 Maximum Position (Heating)

10:08:10 Group 005: Defroster Flap Control Motor (V107)
114.0 Current Value
115.0 Specified Value
25.0 Minimum Position (Lower Stop)
227.0 Maximum Position (Upper Stop)

10:08:10 Group 006: Central Flap Control Motor (V70)
220.0 Current Value
223.0 Specified Value
35.0 Minimum Position (Lower Stop)
220.0 Maximum Position (Upper Stop)

10:08:48 Group 007: Air Flow Flap Control Motor (V71)
22.0 Current Value
19.0 Specified Value
22.0 Minimum Position (Lower Stop)
233.0 Maximum Position (Upper Stop)

10:08:48 Group 008: Air Recirculation Flap Control Motor (V113)
205.0 Current Value
208.0 Specified Value
33.0 Minimum Position (Lower Stop)
205.0 Maximum Position (Upper Stop)

10:08:48 Group 009: Temperatures I
39.0°C (102.2°F) Left Footwell Vent Temp. (G261)
37.8°C (100.0°F) Right Footwell Vent Temp. (G262)
28.2°C (82.8°F) Left Vent Temp. (G150)
28.2°C (82.8°F) Right Vent Temp. (G151)

10:09:23 Group 010: Temperatures II
26.0°C (78.8°F) Evaporator Outflow Temp. (G263)
28.0°C (82.4°F) Fresh Air Intake Duct Temp. (G89)
11.5°C (52.7°F) Calculated Ambient Temp.
22.5°C (72.5°F) Measured Ambient Temp. (G17)

10:09:23 Group 011: Temperatures III
26.5°C (79.7°F) Dash Panel Temp. (G65)
3240 /min Temp. Sensor Blower Speed
90.0°C (194°F) Coolant Temperature
ON Idle Speed Increase Request

10:09:23 Group 012
874 /min Engine Speed
0.0 km/h Vehicle Speed
0 Compressor Torque Status
4.0 Nm Required Engine Torque

10:09:51 Group 013
37.5 % Fresh Air Blower Actuation (V2)
1720 /min Fresh Air Blower Speed (V2)
100.0 % Status Terminal 58d
0.0 % Status Terminal 58s

10:09:51 Group 014
23.2 % Radiator Fan (V7) Requested Value
8.8 % Radiator Fan (V7) Actual Value
Not Installed Air Quality Sensor (G238)
40.0 Fresh/Recirculated Air Request

10:09:51 Group 015
R.wn.h.OFF Rear Window Heating (Z1)
Not Installed Front Window Heating (Z2)
OFF Axiliary Heater Actuation
Not Installed Convertible Top

10:10:20 Group 016: Sun Intensity (G107)
1.74 V Sun Intensity Left Side (G107)
424.0 Sun Intensity Left Side (G107)
1.40 V Sun Intensity Right Side (G107)
308.0 Sun Intensity Right Side (G107)

10:10:20 Group 017
ON Status Terminal 15
ON Status Terminal 75
ON Status Terminal 75
14.00 V Supply Voltage (Terminal 30)

10:10:20 Group 018
00:06 Time
1 Key Number (Ignition)
00000 Windscreen Wiper Status
49.0 % Fresh Air Blower (V2) Duty Cycle

10:10:47 Group 019
0 1 001 Bin. Bits
0 0100 Bin. Bits
Bin. Bits
Bin. Bits

10:10:47 Group 020: Seat Heating (Driver)
0.0 % Switch Position (knurled Wheel)
26.4°C Temperature Actual (G59)
-99.0°C Switch Position (knurled Wheel)
OFF Seat Heating (Passenger)

10:10:47 Group 021: Seat Heating (Passenger)
0.0 % Switch Position (knurled Wheel)
21.6°C Temperature Actual (G60)
-99.0°C Switch Position (knurled Wheel)
OFF Seat Heating (Passenger)

10:11:17 Group 022
OFF Auxiliary Heater (J364) active
0000 Auxiliary Heater Signals
OFF Fresh Air Blower Requ. by Aux.Heat.
3771.4 s Maximum Aux.Heat. Active-Time

10:12:02 Group 026: Fault Code Conditions I
Erased Deactivation Fault Code
Erased Refrigerant Circuit Pressure
Erased Radiator Fan (V7) Requested Value
Erased Radiator Fan (V7) Actual Value

10:12:02 Group 027: Fault Code Conditions II
Erased Calculated Ambient Temp.
Erased Vehicle Speed
Erased Coolant Temperature
Erased

[b1337]

I'm jealous all your actuators work correctly

[S11KA]

I'm jealous all your actuators work correctly

But somewhere has to be a problem and I hope it's not in my head :S

[old guy]

This doesn't look right at all. A 64% duty cycle should be producing a system pressure somewhere around 16 to 20 bar. Are you sure the system is fully charged?


10:07:26 Group 001
0.648 A A/C Valve (N280) Current
64.0 % A/C Valve (N280) Duty Cycle
22.5 % High-Pressure Signal (G65)
6.0 bar Refrigerant Circuit Pressure

[imnuts]

This doesn't look right at all. A 64% duty cycle should be producing a system pressure somewhere around 16 to 20 bar. Are you sure the system is fully charged?

Next thought would be, is the compressor in the loop with the accessory belt and if it is, does the compressor still work.

[S11KA]

This doesn't look right at all. A 64% duty cycle should be producing a system pressure somewhere around 16 to 20 bar. Are you sure the system is fully charged?


10:07:26 Group 001
0.648 A A/C Valve (N280) Current
64.0 % A/C Valve (N280) Duty Cycle
22.5 % High-Pressure Signal (G65)
6.0 bar Refrigerant Circuit Pressure

Pretty sure. They changed the liquid last week. The old amount was 405 mg or ml? and the new one should be 500.

Might there be a problem with High-Pressure Signal (G65)?

[old guy]

I don’t think it is a problem with the high pressure switch since it is reading a low signal (22.5%). That seems to correspond with the low refrigerant circuit pressure.

[S11KA]

Next thought would be, is the compressor in the loop with the accessory belt and if it is, does the compressor still work.

Not sure. Do I need to remove bumper etc. to reach the compressor and the belt?

[Boost92]

Get some gauges and conect to the HP side and LP side. Then you will probaly see whats going on inside the system :)

[old guy]

A 6 bar pressure reading is typically close to what you would see when the A/C system is in a static condition and the high side/low side pressures are equalized. Your 64% duty cycle should be producing significant system pressure. If your system was recently charged with the proper amount of refrigerant and you aren’t building any system pressure you may have a faulty compressor. Another possibility is a defective restrictor valve.

Normally when the compressor is engaged the restrictor valve limits the flow, allowing the high side to pressure to build up. If the restrictor isn’t restricting the flow all that will happen is that the refrigerant will pump around through the system at the same pressure.

As Boost 92 mentioned a proper set of hi/low gauges would help determine the issue.

[john_gonzo]

One easy thing to check: Make sure the center portion of the AC pulley is turning while the engine is running. If just the outer portion of the pulley is rotating then the coupler between the pulley and the compressor shaft has sheared and the compressor guts are not moving.

That is one possible reason for this...

A 6 bar pressure reading is typically close to what you would see when the A/C system is in a static condition and the high side/low side pressures are equalized...

Compressor coupler info: http://www.audizine.com/forum/showth...late-vs-clutch

A bad coupler (non-functioning compressor) should have been noticed during system charging.

[tHatOne guY]

[QUOTE=john_gonzo;11603569]One easy thing to check: Make sure the center portion of the AC pulley is turning while the engine is running. If just the outer portion of the pulley is rotating then the coupler between the pulley and the compressor shaft has sheared and the compressor guts are not moving.

1+ this. Exactly what happen to mine.

[pondside36]

As to not start another thread, I hope the OP doesn't mind I'm having an A/C issue too, basically does not blow cool air.

Checked my clutch and center are spinning. The only code I'm getting is:

Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 G
Component: A4 Klimaautomat 0712
Coding: 00000
Shop #: WSC 63351
VCID: 254F040ABFC79B162D-513C
1 Fault Found:
01592 - Air Quality Sensor (G238)
37-00 - Faulty

I measured these blocks, not sure if they help:

Address 08: Auto HVAC (8E0 820 043 G)

09:37:48
0.652 A A/C Valve (N280) Current
61.2 % A/C Valve (N280) Duty Cycle
23.5 % High-Pressure Signal (G65)
6.0 bar Refrigerant Circuit Pressure
27.0 Current Value
26.0 Specified Value
29.0 Minimum Position (Cooling)
230.0 Maximum Position (Heating)
29.0 Minimum Position (Cooling)
3120 /min Temp. Sensor Blower Speed

[old guy]

I'm certainly no A/C specialist but it looks to me like either your compressor isn't working or your system is really low on refrigerant. A 61% duty cycle indicates that the compressor should be compressing the refrigerant but a 6 bar system pressure is what I would expect to see as a static system pressure. So either the compressor isn't compressing or there isn't adequate refrigerant to compress. You really need a set of hi/low gauges to determine the problem.

[pondside36]

Thanks that was my thought too, need to borrow some gauges from work.

[S11KA]

Problem finally solved and my AC is now working perfectly. Believe or not but even in Finland we have a summer and it’s not a pleasure to drive a black car without an air conditioning.

I took my Audi to my local car service so they could find out what’s the problem. They did their tests and told me that the problem is probably in the compressor and suggested to buy a new one. They said it’s not worth of doing a wide troubleshooting by removing the compressor etc. because it would cost me a lot and they still may not find out the problem for sure. For this they charged me only 30 €. So I ordered a new one Mehr Hella Service compressor from Estonia (about 300 € inc. postals).

They also told me that it would be almost a waste of money to buy a new dryer too because the compressor would be only so short time out of position. And my car has over 300 000km so I don’t wanna spend a lot of money either…

After changing it, which costed about 247 €, the AC is working perfectly.

It was interesting to see that the old one was Hella too and produced in 2011, so it didn’t last very long. It seemed pretty good and maybe someone could have repaired it but I guess the repairing would have costed quite a lot still. I hope this new one will work at least another 5 years.

[old guy]

Thank you for the follow up in the thread I'ts very helpful for future searches.