Ice cold Air con to start then warms up

[harryrope]

Hi, I am sorry to mention Air con - I have a nice cold system for the first few miles on a hot day, but after some time it begins to warm up to a bit and becomes just about the same as no air con.

 

I have vcds but no fault codes have come back on a standard fault scan - would anyone know what tests to run in the hope of finding the problem.

 

Of note, I almost always see large puddles of water underneath the car when its been driven, but have always assumed it to be the condensing process. ?

 

Any ideas or experience of similar faults would be appreciated

 

Steve

 

 

hvac log.txt

Edited 10 May, 2023 by harryrope
typo

[Breezy_Pete]

Check that radiator fan(s) are spinning up if you demand cold air with engine warm.

 

[harryrope]

Thanks Breezy

 

Do you mean the engine radiator fans ?  If so do I just eye ball them in the engine bay ?

 

It does seem to blow cold when engine temp is normal after a short run -

 

Thanks

 

[harryrope]

Here is a few tests I ran with vagcom -

 

Sunday,07,May,2023,23:12:03:19273

www.Ross-Tech.com

 

 

                Address 08: Auto HVAC  (3T0 907 044 BK)

23:11:48
  IDE00198-ENG100282   Refrigerant pressure-MUX Kaeltemitteldruck 9.2 bar
  IDE00966   Compressor current: actual value 0.820 A
  IDE00967   Compressor current: specified value 0.820 A
  IDE00968   Compressor speed 900 /min
  IDE00969   Compressor load 4.2 Nm
  IDE00970-ENG103807   Coolant fan activation: actual value-MUX Lueftersteuerung 26.8 %
  IDE00973-ENG100004   Outside temperature-MUX Temperatur 20.0 °C
  IDE00974-ENG100004   Outside air temperature internally calculated-MUX Temperatur 18.0 °C
  IDE00982-ENG103939   Temperature downstream of evaporator-MUX Temperatur nach Verdampfer 26.0 °C
  IDE00983   Inside temperature 24.2 °C
  IDE01419   Compressor shut-off condition: last Outside air temperature too low
  IDE03009   Start process requested System malfunction

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                Address 08: Auto HVAC  (3T0 907 044 BK)

23:15:59
  IDE00198-ENG100282   Refrigerant pressure-MUX Kaeltemitteldruck 9.2 bar
  IDE00966   Compressor current: actual value 0.820 A
  IDE00967   Compressor current: specified value 0.820 A
  IDE00968   Compressor speed 900 /min
  IDE00969   Compressor load 4.2 Nm
  IDE00970-ENG103807   Coolant fan activation: actual value-MUX Lueftersteuerung 27.6 %
  IDE00973-ENG100004   Outside temperature-MUX Temperatur 19.5 °C
  IDE00974-ENG100004   Outside air temperature internally calculated-MUX Temperatur 18.0 °C
  IDE00982-ENG103939   Temperature downstream of evaporator-MUX Temperatur nach Verdampfer 26.0 °C
  IDE00983   Inside temperature 24.5 °C
  IDE01419   Compressor shut-off condition: last Outside air temperature too low

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                Address 08: Auto HVAC  (3T0 907 044 BK)

23:16:01
  IDE00198-ENG100282   Refrigerant pressure-MUX Kaeltemitteldruck 9.2 bar
  IDE00966   Compressor current: actual value 0.825 A
  IDE00967   Compressor current: specified value 0.820 A
  IDE00968   Compressor speed 900 /min
  IDE00969   Compressor load 4.0 Nm
  IDE00970-ENG103807   Coolant fan activation: actual value-MUX Lueftersteuerung 27.6 %
  IDE00973-ENG100004   Outside temperature-MUX Temperatur 19.5 °C
  IDE00974-ENG100004   Outside air temperature internally calculated-MUX Temperatur 18.0 °C
  IDE00982-ENG103939   Temperature downstream of evaporator-MUX Temperatur nach Verdampfer 26.0 °C
  IDE00983   Inside temperature 24.5 °C
  IDE01419   Compressor shut-off condition: last Outside air temperature too low

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                Address 08: Auto HVAC  (3T0 907 044 BK)

23:16:03
  IDE00198-ENG100282   Refrigerant pressure-MUX Kaeltemitteldruck 9.0 bar
  IDE00966   Compressor current: actual value 0.820 A
  IDE00967   Compressor current: specified value 0.820 A
  IDE00968   Compressor speed 900 /min
  IDE00969   Compressor load 4.2 Nm
  IDE00970-ENG103807   Coolant fan activation: actual value-MUX Lueftersteuerung 27.6 %
  IDE00973-ENG100004   Outside temperature-MUX Temperatur 19.5 °C
  IDE00974-ENG100004   Outside air temperature internally calculated-MUX Temperatur 18.0 °C
  IDE00982-ENG103939   Temperature downstream of evaporator-MUX Temperatur nach Verdampfer 26.0 °C
  IDE00983   Inside temperature 24.5 °C
  IDE01419   Compressor shut-off condition: last Outside air temperature too low

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

Address 0x08,3T0 907 044 BK,UDS Selective Output Tests,IDE01074-Flap motor for fresh air/recirculation air flow flap

 

[Breezy_Pete]

18 minutes ago, harryrope said:

Thanks Breezy

 

Do you mean the engine radiator fans ?  If so do I just eye ball them in the engine bay ?

 

Yes and yes.

[J.R.]

The first thing to look at is the compressor shut down code, it says the last one was outside temperature too low, unless it was below 2°C when the aircon last started going warm (which at 2°C it could not have done anyway) then you have found your problem.

 

Has the car had a parking knock at the front? Has the front bumper been removed?

 

I'm betting that the sensor is not clipped into its proper mounting position, other wise check the connector then replace the sensor if the foregoing did not resolve the problem.

 

You could also check the readings using VCDS, it may be correct at standstill but getting chilled by the airflow when in motion.

[J.R.]

It could also be the compressor  modulating valve sticking, ignore the compressor current and compressor load, they are simply calculated values assuming the modulating valve is doing as its told, look instead at the refrigerant pressure when the cooling stops.

[harryrope]

Thanks J.R and Breezy. 

 

If I can, I'll check all of the above this afternoon after a drive. 

Is it worth hooking vcds up whilst on the drive to monitor? 

 

Steve

 

 

 

 

 

[harryrope]

22 hours ago, Breezy_Pete said:

Check that radiator fan(s) are spinning up if you demand cold air with engine warm.

 

Checked fans both running start running when AC is switched on

19 hours ago, J.R. said:

 

I'm betting that the sensor is not clipped into its proper mounting position, other wise check the connector then replace the sensor if the foregoing did not resolve the problem.

 

You could also check the readings using VCDS, it may be correct at standstill but getting chilled by the airflow when in motion.

Checked the sensor and it is in place 

 

 

[Breezy_Pete]

See what VCDS says about the refrigerant pressure when the engine/car is stone cold (engine not running, just ignition on).

Edited 11 May, 2023 by Breezy_Pete

[harryrope]

Thanks again for the input and apologies for late response....the problem seems to have resolved itself. In Fact, the Aircon has been perfect (until tomorrow of course) although vcds did report some very silly cabin temperatures? 

 

Cheers

 

Steve