Air con not working - conflicting advice from Awesome / Stealth / Skipton Autos...

2002 tdi 75, 138K, well maintained, all services by Audi, Skipton Autos or Stealth.

Recently (at 135k) developed a number of faults - blowing intercooler, tracking needed doing, air con stopped blowing cold.

I took the car down to Stealth for a full service, cambelt, aux belt, water pump, tracking, intercooler, air con re-gas. (£980 well spent, Vince is a gent and his boys know their stuff, just wish it wasn't three hours away...). Vince re-gassed the air con, but it still wasn't working and he didn't know why.

I then had Mike look at the air con problem (he only lives a few miles away) and he pulled up fault codes:
00710 Defroster Flap Positioning Motor (V107)
00601 Potentiometer on Positioning Motor for Central Flap (G112)
00796 Fan for Interior Temp Sensor (V42)
Mike advised that it was probably the positioning flap that was preventing the compressor starting up, and advised taking the car to Awesome to have the work done.

In the meantime my father in law had the air-con system in his A4 looked at by Mr Air Con in Rochdale and was impressed by their work, so I took it there for a diagnostic. He concured with Mike that it was probably the positioning flap that was stopping the compressor starting up. This, he advised, was a ten hour job which involves taking the dash out.

Today the car's been into Awesome for diagnostics on the air con problem, who first tried the Aircon Pressure Swith (£27.48 + £55 labour), that was found to be OK. They have now concluded that its the compressor that's gone, but this is only the opinion of the mechanic, its not based on the fault codes. (the G112 fault code is permanent, the other two clear and then come back). Quote for compressor is £250 + £330 labour to fit.

So I either: Pay Mr Air Con 10 x £40 / hr + parts to take the dash out, fix the flaps, and hope this works, or:
Pay Awesome £600 for a compressor which may or may not work,
in thoery one of them is wrong...
OR do I take it to Audi Manchester for alternative diagnostics, and see what they say.

or has anyone got any other ideas? Cant say I relish spending the best part of £600 on something that might not work! Grrr...

Russ

Can't remember if I tried spinning the centre of the compressor with the engine off, but this is the first thing to check - if the centre spins when the engine is off, then the compressor is goosed.

My second compressor was changed after my 2009 accident and this time there were no real symptoms (other than no cool air) and no pointers (centre of compressor was fine, all switches fine). Following a compressor change, all was well again. Only thing that I could possibly pick up on was that the system was re-gassed and was actually 2 bar over pressure, so this could have caused an internal failure - have you had your system regassed recently?

Cheers

Mike

The system was re-gassed at Stealth, but only after it stopped working...
I can't remember you spinning the centre of the compressor - any chance that you could tell me where it is, so I can try spinning it, or could you PM me if it's easier for me to bob round?
Cheers
Russ

For the benefit of all Russ, to check the compressor centre, do the following:

Take off bonnet and set aside.

DO ALL THE FOLLOWING WITH THE ENGINE OFF!

Looking down into the engine on the drivers side, you'll see the auxillary belt - it runs around the alternator pully at the top and drops down by the intercooler.
The next pully it goes around at the bottom front is the climate compressor.
Put your hand down there and grasp the raised centre portion of the pully - NOT the grooved pulley itself. Try to turn it either forwards or backwards.
If the centre of the pulley moves or spins whilst the outer is static, then the compressor is toast. You could just try replacing the clutch system, which has failed allowing the centre to spin, but then you've got to ask why the clutch has failed.

The clutch system is there so that if the compressor fails internally, the aux belt can still turn and operate the alternator.

Cheers,

Mike

My aircon has also failed, when I took the car to a specialist and they showed me how to check that the pump has failed by spinning the wheel.
They even refilled the gas as it had not runout but did advise that it will need replacing!! He also said that it wouldn't cause a problem for the rest of the engine as it just spins freely when it packs up.

Apologies for not following up on this thread. Shortly after posting I quit my job and set up my own architects practice, so I've been concentrating on that for the past few months - fiddling around with the air con over winter has been a long way from top of my list!
Anyway, things are settling down slightly now and there's a little cash coming free so I can think about getting this resolved before summer. I just tried spinning the centre of the air con compressor, but it's not spinning, there's about 5mm of play but no more. As mike said above, this can still mean that it's goosed.
I guess I'll have to get the compressor relaxed and hope this fixes it.
Don't know whether this is related, but I've also got a noise inside the cabin that sounds like a small motor 'hunting' for a happy position. It sounds like the steering motor on a radio controlled car.

Don't seem to be able to edit that last post - the 'edit post' button isn't visible.
It's meant to say "compressor replaced and" not compressor relaxed and"

Hi Russ, I have just listed a new air-conditioning pump in the for sale section which you may be interested in.
Regards, Clive

Well I've finally got some spare cash. Took it to Mr Air Con and he's replaced the compressor with the one from Clive and....
...it still doesn't work. Ar$e.
He's having a look into the fault codes.

update: he thinks that if three things are coming up as failed, it's more than likely to be the control unit. He's trying to source one to swap, but does anyone on here have a spare A/C control unit that works that I can buy or try?
Cheers
Russ

Before I offer you my spare unit, I would ask what 'three things' are failing? G263? Regulator valve? One of the many temperature probes? Also I would want to know the detail of 'it doesn't work'. Is it totally not working or is it running in safe mode, the mode which for example if the G263 sensor is deemed faulty can be triggered. This turns the system down to using a much lower maximum capacity to protect it. I have experienced and fixed this before and it is very difficult to tell this mode is kicked in unless you measure the pulse voltage from the correct wires on the back of the CC unit with an oscilloscope. Were the fault codes cleared and then came back permanent?

If your man is confident the unit is at fault, I have a spare one. It is the pre-soft touch hard plastic version that doesn't suffer from scratched buttons. There is no cabin temperature sensor fan (at the top of the unit, behind the slots) as I swapped it into my broken one. But you can easily replace with one from your existing unit, only a few small screws. If you really need it, PM me for the sale.

Hi humps, thanks for taking the time to reply with your expert knowledge...
00710 Defroster Flap Positioning Motor (V107)
00601 Potentiometer on Positioning Motor for Central Flap (G112)
00796 Fan for Interior Temp Sensor (V42)
Yes these three faults keep coming back once they are cleared.
I wasn't aware the AC could run in 'safe mode'. It seems to work as it should apart from not blowing cold air - ie the compressor isn't spinning up. The compressor was replaced this morning and this hasn't solved it. I'll forward on your advice re oscilloscope on the back of the CC unit.
How much do you want for your unit? I'm happy to return it if this doesn't solve it...

The first two faults rings a bell, I have not had these issues myself but seem to remember there could flap issues that can be fixed by recycling the flaps. Needs a bit of searching!

I want to laugh at the 3rd error! That's exactly what I used my spare unit to fix it! Which may mean you're out of luck even if you get my unit. See here http://www.a2oc.net/forum/showthread.php?13876-Missing-fan!-(climate-control-interior-temp-sensor) it is very easy to check that little fan is there or not(!) or running or broken wires ...etc, just put a voltmeter across it when running. If you're unlucky like me in the above thread, have a poke around the inside, the fan must be somewhere. A dead little fan can affect temperature control as I experienced but doesn't shut down the system, move the CC unit out, blow air to it to make the sensor think car is warm inside, it should tell the A/C to work hard! But I think the flap issue could be affecting it.

There you go http://www.a2oc.net/forum/showthread.php?8816-Faults-with-automatic-air-condition-(Klimavollautomat) might give you some pointers to the flaps.

I'm slightly worried about your air con man trying to find a replacement unit... But of course, I wouldn't expect him to be an expert in A2 systems.

I've already done the 'flap cycling' just to check it's not a stuck flap, but to no avail (I wasn't holding out much hope). I've forwarded this thread to Mr Air Con so hopefully either the G263 sensor or this self-destructing fan in the CC unit will lead somewhere...

russellbridge said:

I've already done the 'flap cycling' just to check it's not a stuck flap, but to no avail (I wasn't holding out much hope). I've forwarded this thread to Mr Air Con so hopefully either the G263 sensor or this self-destructing fan in the CC unit will lead somewhere...

Click to expand...

Sorry to hear that the flaps aren't responding, I'm afraid I have not needed to fix them (touch lots of wood) so I don't know much about them. But i can confirm with certainty, if your G263 is faulty or CCU thinks it is faulty, a G263 specified fault code will be registered. And with that fault code, the a/c will only run in safe mode. If you don't have that code, it is not G263 (which is a 2 pin resistor thermal probe, it can be measured from wires on the back of the CC unit). If I were you, I'd start research on fixing the flaps and potentiometer. Good luck!

Humps
Many thanks taking the time to reply, not just to me but to all the other posts where you've helped others with faulty G263 sensors etc....

All posts seem to be leading to the conclusion that I'd have to take the dash out to replace the G112/G263/central positioning flap, so I think it needs to go to a garage to get this done given that it's our only car, used every day and I don't have a garage.

Mr Air Con in Rochdale had a diagnostics chap in this afternoon called Jason from Auto-Train in Rotheram and he's tested the compressor and it's all OK. He said that the issue is that the CCU has a live and a switched earth coming from the back of it and it's this switched earth that's not reaching the compressor. He said to test continuity of this switched earth wire first, then swap the CCU, but even if that works it's only a temporary solution as a stuck flap or faulty sensor will cause the same issue in a new CCU. He's recommended a garage in Rotheram called German Auto Care so hopefully it's going into them for a dash out job the week after next.

ps I popped the CCU out and the little fan looks in good order and is spinning OK. I also disconnected and reconnected all connection blocks at the back of the CCU (just in case it was a loose connection) but to no avail. I also tested to see if there's any temp diff between Lo and Lo + Econ but there's not.
I'll report back with results once it's been in.

Good news is that it's had it's mid longlife service oil change and air filter change, so good for another 12k miles or so.

pps error codes pulled up by Jason were:
00601 - G112 Potentiometer on Positioning Motor for Central Flap (hard fault)
00710 - V107 Defroster Flap Positioning Motor
00727 - G135 Potentiometer in Positioning Motor for Defrost Flap
00796 - V42 Fan for Interior Temp Sensor
01272 - V70 Positioning Motor for Central Flap
Russ

Hope you get this fixed soon Russ - I heard a rumor we might get to see some sun in July - frustrating the new compressor didn't do the trick but hope the flap thingy resolves it.

much joy bud? similar ish issue here

For the benefit of all, I've finally fixed this issue. It's a hell of a job getting the dash out and the central tube to get to the V70 motor, but it's now been replaced, and, with a little help from Mike resetting the codes, I now have a 100% fault free A2. (touch lots of wood...)

I had the following fault codes
01272 - V70 Positioning Motor for Central Flap
00601 - G112 Potentiometer on Positioning Motor for Central Flap (hard fault). I don't know what 'hard fault' means but I assume that it was the failure of this part which has caused all the issues.
The above two faults are linked - the potentiometer is contained within the V70 motor (part number A8Z0 819 453 C - £118 inc VAT)

00710 - V107 Defroster Flap Positioning Motor
00727 - G135 Potentiometer in Positioning Motor for Defrost Flap
The above two faults are linked - the potentiometer is contained within the V107 motor. This fault went away when the V70 part was replaced.

00796 - V42 Fan for Interior Temp Sensor
This is the little fan attached to the A/C control panel. This fault went away when the V70 part was replaced.

The following photos show the A2 with the dash and central tube removed just to show others where the V70 and V107 / V68 motors are. The V70 motor is replaceable but requires the dash and central tube out to get to it. I recon this took me 15hrs in total. The V107 and V68 motors require the entire A/C system to come out of the car which would obviously be a lot more work. The V70 job is do-able with a standard toolkit bar a variety of sizes of torx and spline bits (screwfix part# 63378).



Hopefully there are four images uploaded above.

The re-install of the dash generated a load of fault codes - mainly airbag related, but the steering angle sensor lost the centre position too which resulted in having to reset this - many thanks once again to Mike for helping me to clear these codes.

Hope this helps others in some way.

Russ

Wow! ..... don't you just hope that your A2 just keeps going .... and going, without ever getting that type of problem? It is like hoping that you'll never be told that you've got Cancer! UGH, doesn't bear thinking about!

David