A2 1.2 TDI - Intermittent clutch not disengaging.

E

Erling

Member
Car new Sept 2005 and only covered 111,000 miles mainly on motorways, so clutch use probably less than 30,000 miles of urban commuting.

During the last 30k miles I've asked 3 separate UK Audi dealers to check out slow clutch disengagement on downchanges, all no fault found (to be fair, symptom reported has been a low frequency vibration on downchanges/low road speed/light load that I now link to clutch drag).

I now have an intermittent problem of no clutch disengagement and/or gear downchanging braking within first 1-6 miles from some first cold weather (+5 to - 10 deg C) start of the day.

Car stalls in the gear it is stuck in when I slow down. I go through 'ignition off, gear selector lever to stop/park position, press brake pedal, turn ignition key to start' routine and generally car starts OK and its clutch function is restored.
Sometimes I've had to make several attempts before starter will respond to ignition key (back to ignition off, gear selector lever to neutral/drive and back to stop/park position, press brake pedal and turn ignition key to start position).

Brake light switch is confirmed OK!

I noticed RAB's recent comment re clutch adjustment/calibration during routine major service - are UK dealers likely to have done this - or even know they should???

Whatever, any ideas out there in the UK A2 1.2 TDI community as to root cause of my car's intermittent cold weather failure to disengage its clutch and downchange - software/hardware?

Thanks,

Erling
 
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Erling,

Sounds like low or no hydraulic pressure to me. Have you checked the fluid level? Possibly also a failing pump or poor electrical connection to the pump.

Another possibility is that the membrane in the pressure accumulator is failing - not expensive to replace it.

No, I'm not convinced that VAG in the UK carry out gearbox/clutch basic settings. There's nothing in my Lupo 3L service book to suggest that this was done from the time when VW did the servicing. As it needs to be done every other service, there should be. This won't be the cause of your present problem though.

RAB
 
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Rab,

Since ambient temps have risen above zero (last 5 days) all has been normal - no further loss of downchange/clutch function in first few miles from first start of the day.

I'll check clutch hyd system fluid level and hose state during daylight hours this week.

Issue might still be electronics/switchgear if the selector lever switch 'Ecoangel' had problems with can have an intermittent contact problem.

Low frequency vibn/judder remains during low load downchanges - so I still think the long term unresolved clutch drag issue remains.

I'll let you know when I find cause, or if clutch operation goes from intermittent to 'hard' failure state!

Ciao,

Erling
 
Erling,

Looking at www.a2-freun.de, owners do seem to have more hydraulic problems when the weather is colder. It won't be the gear change switch gear if you are in ECO mode though.

When was your last basic setting done? This includes adjusting the clutch. Would any Audi workshop (or VW for that matter) know what to do? Have they ever seen an 085 gearbox before? I used to have my Lupo 3L serviced by VW and I'm not convinced that it was ever done. In fact they seemed reluctant to do anything that involved removing the undertray, including changing the air filter.

RAB
 
Erling,

There is a quick way of checking the health of the hydraulics. Switch on the ignition (but do not start) with your foot on the brake. Wait for the hydraulic pump to stop and put the lever in tiptronic mode. See how many gear changes you can make before the pump restarts.

2 is poor, 4 is moderate and 6 is excellent.

If your fluid level is OK and 6 is not achieved, consider changing the accumulator unless you have obvious leaks.

RAB
 
Poor pressure retention.....

Rab,

Your 'idiots guide' to 1.2 TDI Tiptronic gearbox hydraulic change 'health' really good....and simple enough even for me to grasp and apply.

Static manual selector gear change count result - usually only 2, sometimes 3 changes before the pump starts up again..........

Clearly the hydraulic pressure's going somewhere other than clutch operation and gear changing.

Hope the rain stays away this week-end for me to check oil level and pipes for leaks.

Whatever, as I've got Audi extended warranty I'm not paying for or fitting new pipes, accumulator or pump!

Will keep you posted on progress.
 
Erling,

Judging by the size of the pump, the system functions more on pressure (50Barg) than on fluid movement, so a small leak can make a big difference. If you have no external leaks, poor performance will be due to internal leakage (expensive, for Audi in this case!) or more likely, the accumulator. It has a membrane which deteriorates with time, although one of our Lupo 3L's has a seven year old acc. and still manages six changes. If you have to wait to start the engine after leaving the car overnight, it is a sure sign that the acc. is failing. The accumulator is only £25-30. I hope Audi don't change everything else before trying this option!

RAB
 
Time to start in morning

Re morning starts; have to wait a lot lot longer now than 6 months ago before start cycle will begin. Pump runs and runs - say one minute at least when cold. If engine is left running, neutral selected, for a few minutes to clear ice etc, the engine will stop. Restart is a pain; just as if I'd been driving the car down the road and had it stall on slowing down because the gearbox failed to declutch and change down.
No leak found, so assume its internal and not obvious or the accumulator.
I had another 'running' event on Thursday, in this case I'd been freewheeling downhill in Eco mode 3 mins from home first start of the day, when the clutch/box didn't respond to either throttle demand or pressing the brake pedal. I ended up with the car stopped on a pelican crossing, box stuck in neutral and with a line of traffic behind. Usual drill, Hazards on and everything else off. Handbrake on lever to stop/park and then to ignition back on - it took about 5 start attempt cycles with multiple manual gear selector lever movements in between (panic mode - clearly of no benefit) before eventually the hydraulic pressure recovered. By then, many red facesand even the odd horn - especially when I drove off as everyone behind was in the process of trying to overtake one another.
Will book car in with Cardiff Audi and await the result.........
 
Erling,

Sounds like low oil level in the reservoir or the accumulator has virtually given up the ghost.

Obviously you are losing pressure overnight so you could check the hydraulic level in the reservoir first thing in the morning, without loosening the accumulator. Loosening the accumulator empties all the fluid into the reservoir and allows you to check the level, but before this disconnect the pump - the connector is next to the pump. If you have to loosen the accumulator, because of accessibility it's difficult to loosen with a 24mm spanner but a chain-type filter wrench works well. A torch helps to see where the level is.

If the level is normal, i.e. within the window, then the problem is almost certainly an almost expired accumulator.

RAB
 
All better now!

Car just back from Cardiff Audi; had been waiting 5 days for parts on back order.

I'm told the gearbox hydraulic actuator assy, hydraulic pipes and seals all replaced and clutch system settings adjusted. All seems OK and total absence of electric pump sound too. No sight of job card to confirm exactly what was replaced due my late drop off of loan car.

Seems the Audi extended warranty premium has again more than paid for itself!

I'll have to see what else is odd/faulty before the 'all components' warranty runs out in June!

Erling.

PS: Covered over 1500 miles in an A4 Avant 2 litre TDI 8 speed DGS loan car - averaged 44 mpg, which isn't bad considering average speed of 48 mph. Couldn't avoid playing with DSG box Drive manual mode and Sport setting once I'd realised it had 8 speeds.........now how would that suit Mike's Tank?
As for the A4.....not my cup of tea, though wife thought it was OK. New A1 is looking more interesting as info emerges.
 
Erling,

Any evidence that the accumulator was changed? If not and the car is OK now, then presumably the clutch was not working because too much pressure was being lost in the gear actuator and the pump couldn't keep up. How many changes now without the pump restarting?

RAB
 
Still only 2 to 3 changes before pump start

Hi RAB,

Silly me......until you asked I hadn't checked changes before pump starts to run!

Exactly the same as before......and not having used the car for a couple of days, the pump ran when I opened the door for about 10 seconds which is however a lot less than before the dealer visit.

I haven't lifted the engine cover off to check whether accumulator replaced, but dealer said no when I asked.

They said problem was caused by oil loss due to leaks from seals in gear actuator assy, hence replacing it.

Hmmm, I'll need to check out what's been done as it seems the system is working, but not retaining static pressure........either its still leaking fluid/pressure somewhere, or the accumulator's still 'iffy'.

Thanks for prompt,

Erling
 
Hi Erling,

There is one metallic seal on the gear actuator that VAG used to supply but do not now! There are at least three other sources for this seal including www.a2-freun.de. That's the most likely to have failed but I'm not sure that it would have caused your problems; if so you would have been topping up the hydraulic fluid on a fairly frequent basis. I still think that you need a new accumulator - it's only about €30 and takes about two minutes to change; a new gear actuator is about €1,000 and you can add a few hours labour at least! Just as well that you're not paying!

RAB
 
Still puzzled...

Hi RAB,
I think Cardiff Audi replaced the whole gear actuator assy, plus connecting pipes. However, I can't check until Weds at earliest as its dark when I leave for work and return home. Assuming they did as they said, the original accumulator will still be on the car - in which case I've got to justify it being replaced. This may be difficult as the car no longer stops tdead - a hard and irrefutable fault.

Incidentally, can't find where to look on A2 De owners site for the metal seal you mentioned.

Can you send a page link or other source - sounds like I should get one to go with my other must have spares.

Is the part shown in EKTA (mine's a 2005 copy)?

Ciao,

Erling
 
Erling,

The stalling may have been due to a lack of hydraulic oil because of the supposed leak. If the gear actuator had been leaking, you would have seen oil where you normally park as the actuator is behind the undertray. If it was the metal seal that had failed, then Audi would have replaced the actuator because the seal is no longer a service part. Assuming that there is nothing else amiss, with a new actuator and a perfect accumulator, you should get five/six changes before the pump starts. Both our Lupo 3L's manage six changes currently, one with an eight year old accumulator. Changing the accumulator on the other recently, increased it from four to six. Both have their original gear actuators. Incidentally they both have their original batteries too (1999 & 2001)!

RAB
 
Saga continues.

Hi RAB,

Car left with Cardiff Audi last week to look at reason for oil on floor post gear actuator replacement. No fault found, oil assumed to be from excess overspill from resevoir or traces from original leak. Did however consider my car's battery could be at fault..........and then decided it wasn't faulty as it was OK after charging, though found slight discharge which they attribute to RNS-E unit - fitted by others (meaning now't to do with them or Audi).

No attempt/record of them checking accumulator function or its ability to retain pressure overnight etc.

Checked max number of changes again at dealer and this remains 2 before pump starts to run. That's with following new items fitted and clutch/change system recalibrated the week before:
085 142 409 Shift selector (£975.66)
085 142 418 B Tube (£ 33.92)
085 142 417 B Tube (£ 33.92)
085 142 419 Ret spring (£ 5.51)

Total with 3 litres hydraulic oil, labour less 15.55 parts discount plus VAT = £1317.68.
Fortunately every penny charged to Audi's All Component extended warranty (more than double premium I paid).

I've therefore checked price of the unchanged and still suspect accumulator, pt no 6N0 142 433.....and its a little more than you recall @ £84.14 plus VAT. Maybe that's the Audi price and the VW equivalent will be somewhat less? I'll check before committing myself.......

Anyway, I've at least established a new gear selector assy and key pipes fitted to stop previously unnoticed oil leak that resulted in earlier system intermittent fault during very cold weather.

I'll let you know what happens once I've fitted a replacement accumulator. I've also now got a litre of hydraulic fluid in the bootwell - just in case of another leak!

Regards,

Erling
 
Tiptronic Hyd Accumulator - 6N0 142 433

For fellow A2 1.2 TDI owners.....

VAG price consistent between Audi and VW dealerships @ £84.14 plus VAT.
Ditto for 'consumable' O ring seal 6N0 142 435 @ £1.51 plus VAT.

If you have Audi warranty, there doesn't appear to be an Audi dealer diagnostic check that will assess accumulator performance/function. You'll need to find a dealer that will listen to your concern and fully assess/diagnose Tiptronic system performance.......Cardiff Audi doesn't.

So I'll need to shop around for discounted new accumulator to fit myself....

If you don't have any warranty cover, and you're concerned about the 'performance' of your car's Tiptronic gear change system, RAB's simple function check is an excellent base line diagnostic tool.
So:

1. Check number of gear changes before pump restarts - see 'RAB' function check above.

2. Check for hydraulic oil leaks - if found see links above for seal replacements, incl gear actuator internal seal replacement via German A2 Owners Club sourced seal as an alternative to new assy @ £1000+.

3. Check oil level in resevoir - see other links for methods/shortcuts.

4. If less than 3 gear changes achieved in check 1, no substantial leaks found or corrected following check 2, and oil level OK check 3 - change accumulator 6N0 142 433.

This should restore car's Tiptronic hydraulic system pressure retention and 'RAB' function check gear changes to circa 5 to 6 before pump restarts.

......and may your Tiptronic system now perform as intended!

Erling
 
Erling,

I've recently bought two accumulators from Caffyns (VW) Eastbourne (01323 301407) and both were less than £30 with VAT! Obviously the Welsh £ is worth a lot less than the English! Or should that be the Audi £? It's also less than two minutes work to change it so the extra is not labour, unless Audi charge 1/2 hour for two minutes!

It could of course be that they have run out of old stock. These parts, I believe, are made by Hilite who also made the actuator and the control unit (and also supplied equivalent parts for the Ferrari 355 & 360!).

The part no. is identical for the Lupo 3L & FSI.

RAB
 
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Hi RAB,

Thanks for info.

VW stealers in Cardiff used on line EKTA to check stock and price.....as with their Audi equivalent some 6 miles away, EKTA punched out same price and 'back-order' on Germany statement.

I won't even bother dropping by the local Ferrari dealer's parts counter..........

I'll call Caffyns tomorrow though!

Ciao,

Erling
 
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