HVAC error

[ryan-re]

Had a scan done on my car yesterday and had this as the only error:

 

Address 08: Auto HVAC        Labels: 1K0-907-044.lbl
   Part No: 1Z0 907 044 H
   Component: ClimatronicPQ35 084 0305  
   Shop #: WSC 00000 000 00000
   VCID: 3B7F29357A7E811

1 Fault Found:
00229 - Refrigerant Pressure
            001 - Upper Limit Exceeded - Intermittent

 

ross-tech only have onfo on lower limit not upper limit. Anyone got any ideas?

 

I had it re-gassed last year and due to it not getting cold I got them to re-do it and test it for issues at the same time and nothing came up.

[mannyo]

Looks like they put to much gas in, as the system comes into use the pressure rises and this could be what you are seeing. Pressure is ok till you switch on the AC, and then it rises to much. You should have a fault frequency which shows how many times the error has occurred.

[ryan-re]

I dont see anything. Could post the whole log file if it helps?

[PerformanceDiesel]

Could be failed high pressure switch. It could be right pressure but switch reporting wrongly or connection to switch has broken down?

[ryan-re]

it was showing about 17mb when on full whack

[PerformanceDiesel]

17mb thats low? what reading was that from?

[dstev2000]

When you switch the A/C on, does a fan start up behind the radiator? 

 

Even in cold weather, the refrigerant needs air to pass over the condenser coil to force the refrigerant to condense into a liquid. If it doesn't the condenser fills with vapour and the pressure rises pretty quickly. 

 

Not sure if the refrigerant high pressure is monitored by a basic open/close secondary switch, or just via the pressure transducer which would also regulate the fan speed to prevent the refrigerant from over-condensing which in turn would freeze the evaporator.

 

You should see a refrigerant pressure measured in Bar, if that figure of 17 is indeed the gas pressure, that's a condensing temperature of around 64ºC which is really high for R134a.

[ryan-re]

17 is what vcds was showing when we looked at the real time readings. My mate had some info on his A4 which said it should be around 13 so i guess mine should be similar