Thread: Air con refrigerant pressure reading A4

Morning.

Out of the blue, my air con stopped working (Econ light on permanently). I read the threads on this forum - (which were very useful) and did a VAG COM. I was getting an 00819 high pressure sensor (G65) warning. I tried clearing it but it kept coming back, then whilst doing the measuring blocks, the light went off. These are the readings I subsequently got:

Current 0.432A
Load 20%
Load 42.1%
Absolute Pressure 5%

Can anybody help me to make sense of them please i.e. is the absolute pressure referring to the refrigerant, and is this OK?

I'm trying to work out whether I just need a new sensor or a re-gas (or both).

The car is an A4 avant 2004 1.8T S Line

Very many thanks in advance.


Beef

Sorry for the delay getting back to you mate, been a bit busy.

I don't have a lot of experience in the terminology used by VCDS for their fault codes. Normally when a sensor is broken it says something like 'open' or 'short' but as yours says high pressure warning I reckon that might be saying that there is actually a high pressure problem in the system, but then your readings contradict that if I'm reading them right!

I would say the best thing to do is pop to an air con specialist and ask them to check the pressure. It takes them 2 minutes to put the gauges on and if it's not high then most likely the sensor is knackered.

The thing with high pressure faults is they won't normally appear until after the system has been running for a few minutes. One common reason for a high pressure fault is a blocked evaporator matrix. The air can't flow through it fast enough to warm the refrigerant up and the system effectively backs up, there's then a build up of pressure and the HPCO trips. If your symptoms are appearing straight away (after the car has been sat for a while) then this won't be the case.

Very many thanks indeed, I will do that, although bizarrely since running the measuring blocks, the fault has gone and air con is working fine. I will get it checked out all the same. Thanks for the advice about the evaporator, I hadn't considered that.

All the best,


Beef.

Let us know how you get on mate