Hi all,

Wondering if some brave soul might have any thoughts as to why or how to diagnose one of our cars as Air Con isnt working!

Driving from Cambridge to Surrey 7 days ago - working. Turned on 3 days later and not working, so thought get it re-gassed - told by the independant that gas pressure is bang on... SO!

**Checked with VCDS - No faults

**Gas pressure checked, fine.

**Monitored with VCDS while flicking AC button ON/OFF:

on a working Fabia VRS - compressor duty cycle at 100% (fans kick in)

on non working Fabia VRS - 80% duty cycle(fans not kicking in)

Any help appreciated big time! (Can get logs/try out procedures)

Im having the same sort of problem, ac decided to pack up, checked with VCDS which indicated the G65 sensor was shot, had this and associated pipework changed by VW specialist, got a phone call to say all done, when we got there car was back in the garage and warm air con again, the mechanic ran some logs, not sure of exact problem (he knew, but i didn't take in fully what he was saying) but he said it was most certainly the compressor that had failed?

£400 job to replace and fit, great!! (may try to source a 2nd hand one?)

Hope yours is something less exspensive!

A fault will be logged with G85 if the pressure is low, this doesn't mean the switch is faulty, and it just screws in so no other pipework would be needed. On the Octavia 2 you can check the shut off code and compressor load/current with VCDS. It probably is a compressor failure, depending on if the compressor has seized or not will determine if the system will require flushing of not before the new compressor is connected or it's not going to last long.

Also worth noting pressure does not indicate refrigerant quantity. A canister of R134a will have the same pressure inside it with 13.5 kg of gas/liquid in it as one that has 5 kgs in it at the same temperature..

G65 showed as fault and kept tripping a fuse, this was changed now no fault, air con worked for a while but not now? intermitent? dead?

Any idea exactly how to check the compressor with VCDS?

Soooo why is this fricking car not running at 100%! Swapped the high side pressure sensor, and evap sensor from the good car and no luck :(

....surely its pointing towards a compressor failure??

Not that I fully understand how compressors work, but how can it declare its running at 80% if its broken? I wonder if I could run an output voltage supply from another vrs as an input to the pump on the "broken vrs" and see if it still only gets 80% duty!? Hmm Nutty Prof side coming out!

Not that I fully understand how compressors work, but how can it declare its running at 80% if its broken? I wonder if I could run an output voltage supply from another vrs as an input to the pump on the "broken vrs" and see if it still only gets 80% duty!? Hmm Nutty Prof side coming out!

Hi Nick,

sorry to bother you but after spending days searchingthe internet came across your post.

I have exactly the same problem although I must admit it is not on a Skoda but a VW T5 but which I am sure use the same componets.

VCDS No fault codes

Compessor about 80% duty cycle

Fans tested via VCDS & work but dont come on with Air con.

When turning air con on & off no noises from compressor or changes in engine revs but VCDS reconises it is being turned on & off.

High & Low pressure switches have been replaced by the garage

System has been regassed.

Didnt know if you had found the problem

thanks

Simon

I appear to have a similar problem. had the system regassed by Kwick Fit who advised me that the AC compressor was not kicking in so recialmed the fee from KF.

Mechanic has checked the fault codes and nothing has registered, I do not get any indication on the rev counter that the AC has kicked in so I am at a loss.

The wifes polo also has AC and you can see this system kick in bu a silght movement on the rev counter so I know my system is not working. Has anyone got any ideas on ways to resolve the issue, other wise very pleased with the car which is returning 60+mpg may be I just open the window.

Ok because the compressor is not kicking in doesn't necessarily mean it's broken, there are certain operating conditions which have to be met before the ac will turn on, try looking in the measuring blocks at the evaporator temp switch, iirc it switches off the aircon completely if this reads below zero degrees to stop the evaporator from freezing, also there i think some of the systems use the ambient temperature sensor too, so I guess if you check what the temp readout is on the dash it could give you a clue as to what the aircon is seeing, if the ambient temp is below 2 the aircon will be permanently switched off.

Of all the guesses it's probably the compressor mate, there are a surprising number of octavias/fabias etc for sale 'needing air con regassing' lol