Hello,

I've searched for an answer but can't seem to find anything.

Owner of Skoda Fabia X Reg and still love it.

When I press the A/C button, the rev counter goes up from 900 to 1100 roughly, but the A/C only works (please don't laugh) when it's not too hot outside... It seems that anything above 25c and it's not kicking in. The interesting thing, if I drive through a colder patch (forest, tunnel) it then starts and once it's on, it remains on even when it gets hotter, as long as the engine isn't turned off! I've had the A/C re-gassed 2 years ago so I don't think it's that. There is also a strong musky smell when the A/C first comes on.

Any ideas?

Thank you =)

The AC on my '05 Fabia doesn't seem to be taking to well to this bout of warmer weather either. Doesn't seem to have anything like the power it's usually had.

I've also started noticing a pretty loud, constant hissing from behind the vents when it's on?!?

Not sure if it needs a regas, or whether it'd benefit from a replacement of the evap sensor?

2003 16v 100HP saloon with manual aircon (Not climatic).

Aircon went totally u/s last year. So, on the annual service in March dealer re-gassed it - did not solve the problem.

Then later on the dealer replaced the evap sensor @£100 all-up cost to me.

Now i've got the same problem as the original poster. Aircon works, but only intermittently, and prefers to put-out fully chilled air at temperatures below 20C. If outside temperature is above that then, at the full cold setting it outputs air at slip stream temperature for about 20 minutes running then switches to full cold.

I've concluded that its the temperature flap sticking when the dashboard gets hot in direct sunlight. Once the blower has been running some time, it seems to cool the passage ways down and the temperature valve then moves to the fully cold position. I think this problem occurs mainly on older cars because parts move permanently out-of-position through a repeated heat/cool cycles and the plastics lose some of their elasticity with age.

Reports on the interweb confirm that this is a common problem with aircon across the Volkswagen group with fabias, octavias, Polos, Leons and these reports recommend (incorrectly, IIMHO) replacing the temperature flap motor - this involves removing the lower dashboard on the passenger side, part of the centre console - about 2 hours labour + parts (£200) - I think all that's needed is to put the ducting back into the correct position. I don't think dealers like doing this job cause its a fiddly nause and operating near the passenger's airbag runs the risk of accidentally setting it off.

Interestingly, I've been doing VAG COM reports on my car since 2005 and its always thrown-up temperature flap as a fault. Its only last year that the output of the aircon has been effected. Presumably dealer has done VAG diagnostics on the last 5 annual services and must therefore have spotted this - but has done nothing - car was under manufacturer's warranty up to 2006.

In cooler evening air I have reset, using the adaptation software, the out-of-bounds flap values for the aircon module displayed on VAG COM. And this has done the trick - but it only lasts until the next hot-day.

I have found that occasionally turning the temperature control from full cold to full hot several times in a steady and progressive way can free-up the stuck valve.

I also wonder whether a fault with the temperature sensor that supplies the reading in the instrument binacle also may contribute to this problem. The other day when i started the car at mid-day after it had been standing in the work car park under direct sun since 10:00 (Met office reported temperature was 27C), the instrument binnacle temperature reading showed only 21C !!!!!. After 5 minutes running it rose to 27C. Does anybody know what sensor supplies this reading - won't be amused if its the evap sensor and they've fitted the wires wrong way round !

I believe slight increase in engine RPM when aircon button is pushed is normal as ECU is programmed to fuel the engine slightly more to take account of the increase in load occasioned by operation of the aircon - I think the aircon is a clutchless design and operates by controlling the amount of fluid going through the compressor using electrically controlled valves.

Musky smell may mean that the pollen filter needs replacing.

Nick

Edited 29 June, 201016 yr by Clunkclick

I'd have a hunch that the air temperature flap motor is goosed. I think that probably its the positional feed back that is failing - probably the track gets dirty and demanding HOT>COLD>HOT>COLD etc cleans it up enough for it to work for a short time. If the AC is stopping chilling when the outside temperature is high then I'd guess that it could be either that its been gassed up too much so it trips out on HP (high pressure) or similarly an HP trip due to condenser cooling fan controller failure or the condenser fins are choked with leaves etc. VAG COM or VCDS should be able to see what is causing the problem at higher temperatures. There are lots of other possibilities including moisture in the system causing ice pellets, or a low charge (due to leaks) causing it to trip out on LP (low pressure) when the demand is high or -----------.

Edited 29 June, 201016 yr by rum4mo

I have exactly the same problem as alanUK78. It's pretty useless really as you can do without it under 25C. Im pretty sure ive got enough gas in it as I hardly use it unless it gets too hot. This problem only started this year. Gonna try to live with it as I am looking co change cars in a few months!

This is an extract from the VCDS report before I did the adaptation showing the faulty modules. Once the adaptation was done the italicised fault items disappeared:-

VCDS Version: Release 908.2

Data version: 20100326

Nick

Monday,24,May,2010,21:18:26:08693

Chassis Type: 6Y - Skoda Fabia I

Scan: 01 02 03 08 09 15 17 19 25 37 44 46 55 56 76

VIN: ******************** Mileage: 73960km/45956miles

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

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

Address 08: Auto HVAC Labels: 6Q0-820-045.lbl

Part No: 6Y0 820 045

Component: Klimaanlage X0830

4 Faults Found:

01596 - Motor for Outside/Recirculated Air Flap (V154)

30-10 - Open or Short to Plus - Intermittent

01271 - Positioning Motor for Temperature Flap (V68)

29-10 - Short to Ground - Intermittent

01596 - Motor for Outside/Recirculated Air Flap (V154)

41-10 - Blocked or No Voltage - Intermittent

01596 - Motor for Outside/Recirculated Air Flap (V154)

29-10 - Short to Ground - Intermittent

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

Address 09: Cent. Elect. Labels: 6Qx-937-049-C.lbl

Part No: 6Q1 937 049 C

Component: 00 BN-SG. 1S33

Coding: 17418

Shop #: WSC 25040

1 Fault Found:

01054 - Power Supply Relay; Terminal 30 (J317)

28-00 - Short to Plus

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

End ------------------------------------------

Thank you for all the replies, it makes for interesting reading.

Clunknick, I'll try the full cold to full hot slowly trick tomorrow... Funny enough, as my car was parked in the staff car park today (which is in the shade), when I got into my car, the outside air temperature indicator displayed 22c and my A/C started first time, it stayed on all the way home, despite temperatures rising to 27c on the M3. The air was very cold, proof that there is plenty of gas left in the system to work.

I don't understand any of the last reply with the extract from the VCDS report, but it looks fascinating!!

Thank again guys.

I'm thinking of taking it to the garage but don't know whether to go for Skoda main dealership, or the independent garage on the A30 on my way to work, they specialize in A/C repairs... If it's anything over £200, I'll stay A/C free until it's time for a new car. It's England after all, not Florida!

I think that you have proved that the chiller side of the A/C can be made to work, so a trip to an A/C specialist without any kit to diagnose the VAG control side of things will probably be a waste of time and maybe money.

The copy of the VAG-COM or VCDS report showed that that car showed that the temperature flap motor and the outside/recirculating flap motor were either faulty or having a problem. The routine in VCDS for establishing basic settings to let these motors find or re-learn their electrical "end stops" was run and then the car was scanned again. In this case the outside/recirculating motor responded well to being "re-taught" its end stops - but it remains to be seen if this motor is now 100% okay. The temperature flap motor did not respond to being "re-taught" so it still appears to be faulty. These flap motors are not very robust, so they should only driven when they are are needing to be moved - ie they are not made to sit stalled as they would be when they have moved their flap to either of the mechanical end stops, so they are provided with a simple form of voltage feedback which will just be something like a resistive track like a pot - when the control circuit "reads" the motor's new position after its been asked to move, in the case of the end stops, it will stop trying to drive it which would lead to the motor windings getting a bit too hot.

Does that make any sense?