Hi!
I'm having an issue with the A/C in my 2008 R5 Touareg. About a month ago the A/C stopped working and only blew warm air. When I queried the fault codes using VCDS, I got the following results:
Anyway, after that the A/C was working again for a while. But then after probably two weeks, the same fault code has popped up again. The interesting thing was that the A/C still seemed to work, but VCDS showed me the same "Loss of Refrigerant" code:
So, I cleared the fault code, and the A/C kept working for up until now. I haven't seen the fault returning either. But today the A/C stopped working again (only warm air coming out). And the fault code is here again:
After coming home and leaving the vehicle standing (with of course engine off) for about 3 hours, I also queried the measuring blocks:
Now this seems very odd to me, because at the same time I get:
Could it be that my A/C issues are not actually caused by a leak, but by some sensor issue, which send temperature values to the control unit that are way off the actual temperature?
As far as I know the control unit calculates refrigerant mass (and thus loss) from temperature and pressure, and if the temperature sensor would be defect and reporting too high temperatures albeit with normal pressures, the control unit could reasonably assume that refrigerant has leaked out (because if the temperatures would be really that high as reported, the pressure should be much higher too, if the system still contained the required amount of refrigerant).
Am I right about this and with my logic? Or did I miss something here?
If I'm wrong and the data is not conclusive, how would you proceed in finding the actual source of the problem/leak in the system?
Thanks for your help.
I'm having an issue with the A/C in my 2008 R5 Touareg. About a month ago the A/C stopped working and only blew warm air. When I queried the fault codes using VCDS, I got the following results:
00445 - Loss of Refrigerant
000 - -
Freeze Frame:
Temperature: 93.0°C
RPM: 800 /min
Absolute Pres.: 6.0 bar
Load: 51.0 %
Temperature: 24.0°C
Temperature: 28.0°C
Load: 2.4 %
Temperature: 86.0°C
I've cleared the code, but the A/C still didn't seem to be working (only warm air blown out). So, I took it to the dealership, where they topped the refrigerant up. They also did a leak check, but didn't find any.000 - -
Freeze Frame:
Temperature: 93.0°C
RPM: 800 /min
Absolute Pres.: 6.0 bar
Load: 51.0 %
Temperature: 24.0°C
Temperature: 28.0°C
Load: 2.4 %
Temperature: 86.0°C
Anyway, after that the A/C was working again for a while. But then after probably two weeks, the same fault code has popped up again. The interesting thing was that the A/C still seemed to work, but VCDS showed me the same "Loss of Refrigerant" code:
00445 - Loss of Refrigerant
000 - -
Freeze Frame:
Temperature: 96.0°C
RPM: 800 /min
Absolute Pres.: 9.0 bar
Load: 51.0 %
Temperature: 22.0°C
Temperature: 23.0°C
Load: 23.2 %
Temperature: 87.0°C
000 - -
Freeze Frame:
Temperature: 96.0°C
RPM: 800 /min
Absolute Pres.: 9.0 bar
Load: 51.0 %
Temperature: 22.0°C
Temperature: 23.0°C
Load: 23.2 %
Temperature: 87.0°C
So, I cleared the fault code, and the A/C kept working for up until now. I haven't seen the fault returning either. But today the A/C stopped working again (only warm air coming out). And the fault code is here again:
00445 - Loss of Refrigerant
000 - -
Freeze Frame:
Temperature: 101.0°C
RPM: 800 /min
Absolute Pres.: 6.0 bar
Load: 31.0 %
Temperature: 26.0°C
Temperature: 29.0°C
Load: 0.0 %
Temperature: 86.0°C
000 - -
Freeze Frame:
Temperature: 101.0°C
RPM: 800 /min
Absolute Pres.: 6.0 bar
Load: 31.0 %
Temperature: 26.0°C
Temperature: 29.0°C
Load: 0.0 %
Temperature: 86.0°C
After coming home and leaving the vehicle standing (with of course engine off) for about 3 hours, I also queried the measuring blocks:
Address 08: Auto HVAC (7L6 907 040 AF)
19:14:56 Group 016: Refrigerant && Coolant Fan Activation
115.0°C Refrigerant Temp. (R134a)
29.0°C Temperature
0.0 % Cooling Fan Control (spec.)
10.0 % Cooling Fan Control (act.)
19:14:56 Group 016: Refrigerant && Coolant Fan Activation
115.0°C Refrigerant Temp. (R134a)
29.0°C Temperature
0.0 % Cooling Fan Control (spec.)
10.0 % Cooling Fan Control (act.)
Now this seems very odd to me, because at the same time I get:
19:14:31 Group 011: Temperature
29.0°C Outside Air (G17) Temperature
36.0°C Interior Temp. Sensor
36.0°C Fresh Air (G89) Intake Duct
72.0°C Coolant Temperature
19:14:38 Group 015
8.0 bar Refrigerant Pressure (G454)
37.0°C Evaporator Temperature (G308)
0 /min Engine Speed
0.0 km/h Vehicle Speed
Which would mean, that after 3 hours standing still the Refrigerant Temperature is still +40°C above engine/coolant temperature (which is 72°C) and 80°C above environment and evaporator temperature (which are at 36-37°C). Why would the refrigerant temperature be still that much higher, even if it ever really was?29.0°C Outside Air (G17) Temperature
36.0°C Interior Temp. Sensor
36.0°C Fresh Air (G89) Intake Duct
72.0°C Coolant Temperature
19:14:38 Group 015
8.0 bar Refrigerant Pressure (G454)
37.0°C Evaporator Temperature (G308)
0 /min Engine Speed
0.0 km/h Vehicle Speed
Could it be that my A/C issues are not actually caused by a leak, but by some sensor issue, which send temperature values to the control unit that are way off the actual temperature?
As far as I know the control unit calculates refrigerant mass (and thus loss) from temperature and pressure, and if the temperature sensor would be defect and reporting too high temperatures albeit with normal pressures, the control unit could reasonably assume that refrigerant has leaked out (because if the temperatures would be really that high as reported, the pressure should be much higher too, if the system still contained the required amount of refrigerant).
Am I right about this and with my logic? Or did I miss something here?
If I'm wrong and the data is not conclusive, how would you proceed in finding the actual source of the problem/leak in the system?
Thanks for your help.
