Audi A2 1.2. TDI 2002 Gearbox hydraulics problems

E

entotre

New Member
Hi guys, first post here after purchasing a cheap A2 1.2. TDI recently. Looking forward to many miles in this car, but am facing some issues with shifting...
  • Symptoms are that during driving the gear gets disengaged and you cannot rev the engine(some sort of safety mode?). Turning off ignition and restarting will get the car going again.
  • To be able to drive the car I have to switch to tiptronic and stay in 1-4th gear and stay away from low revs. If 5th is engaged it usually disengages gear within a minute or so.
  • Did the pump pressure test as descisbed many places and get only 2 shifts before pump starts. Not good.
    • Video that shows the test:
I wanted to check with you guys what is the best approach to this problem? I am thinking the cause probably is one of the following
  1. Leak in hydraulic shift/clutch system for gearbox
  2. Faulty accumulator
  3. Weak pump?

Questions:
  • Is the best approach to take the full hydraulics system out of the car like in the illustration picture below ?
    • Am I correct in assuming that this is a closed system so it should be possible to remove the whole thing?
    • If so can it be pressure tested somehow? With compressed air maybe?
  • Or is there a better way to approach this?
  • Also wondering what fluid is correct for filling up this system?
  • Is it a good idea to drain it and fill it up after repair. (If a leak is the cause of course...)
Any pointers are greatly appreciated! From a new A2-owner.
49832
 
Hi and welcome to the UK A2 forum :)

Not many 1.2TDI owners on here because it was never sold new in the UK, however a few examples have been imported. @RAB is the man who really knows his stuff on these cars, hopefully he'll see this tag and be along to help you.
 
The quickest thing to try is to change the accumulator. The accumulator contains nitrogen which over time leaks away. Nitrogen can be compressed whereas oil cannot so less nitrogen means less storage for pressurised oil; this might result in there not being sufficient pressure to operate the actuators so drive is disabled. You should also check the oil level in the reservoir (container with green cap). Shortage of oil will have similar consequences to lack of pressure.

To check the level, unplug electrically the hydraulic unit and with a 24mm spanner, unscrew the accumulator half a turn. Check the level in reservoir; it should be within the rectangle of the reservoir. Top up with VW power steering oil. Retighten accumulator and plug in electrical connector.

Now that you have removed the system from the car, you'll have to do a basic setting with VCDS before you can use the car again. This should be done every 30,000km or less. With a 1.2, VCDS will soon pay for itself!

RAB
 
You may also have problems associated with the turbo, e.g. disconnected or non functioning pneumatics. Problems with the transmission don't affect engine revs apart from disabling the accelerator completely.

RAB
 
RAB said:
You may also have problems associated with the turbo, e.g. disconnected or non functioning pneumatics. Problems with the transmission don't affect engine revs apart from disabling the accelerator completely.

RAB
Click to expand...
Hi RAB, thank you for your reply. The engine revs are not affected at all only cutting out throttle when gearbox disengages. So I guess that could point in the direction that the turbo is ok. The car runs great when I stick it in tiptronic and don't go higher than 4th.
 
Proghound said:
Hi and welcome to the UK A2 forum :)

Not many 1.2TDI owners on here because it was never sold new in the UK, however a few examples have been imported. @RAB is the man who really knows his stuff on these cars, hopefully he'll see this tag and be along to help you.
Click to expand...
Thank you Proghound!
 
RAB said:
The quickest thing to try is to change the accumulator. The accumulator contains nitrogen which over time leaks away. Nitrogen can be compressed whereas oil cannot so less nitrogen means less storage for pressurised oil; this might result in there not being sufficient pressure to operate the actuators so drive is disabled. You should also check the oil level in the reservoir (container with green cap). Shortage of oil will have similar consequences to lack of pressure.

To check the level, unplug electrically the hydraulic unit and with a 24mm spanner, unscrew the accumulator half a turn. Check the level in reservoir; it should be within the rectangle of the reservoir. Top up with VW power steering oil. Retighten accumulator and plug in electrical connector.

Now that you have removed the system from the car, you'll have to do a basic setting with VCDS before you can use the car again. This should be done every 30,000km or less. With a 1.2, VCDS will soon pay for itself!

RAB
Click to expand...
Excellent info! I have not actually removed the system, the picture is from someone else on the internet. I will check where I can find any oil leaks when inspecting it. If not I will probably try the accumulator first as you say...checking prices now... :)
 
entotre said:
Hi RAB, thank you for your reply. The engine revs are not affected at all only cutting out throttle when gearbox disengages. So I guess that could point in the direction that the turbo is ok. The car runs great when I stick it in tiptronic and don't go higher than 4th.
Click to expand...

A GGE is a transmission basic setting. Going into safe mode or not being able to use fifth gear does indicate a problem with the turbo.

RAB
 
RAB said:
A GGE is a transmission basic setting. Going into safe mode or not being able to use fifth gear does indicate a problem with the turbo.

RAB
Click to expand...

I love it when people who know shares their knowledge!
  • Oh really? Wow, hope the turbo is not gone.
    • How can I diagnose this? Is there a test that can be done?
  • Ok, I see. Is there a description of doing GGE somewhere? I guess I should try this...
 
Check all the turbo pneumatic connections - at top left, looking from the front. They are easily disconnected.

Check the VNT actuator - with the engine off, you should be able to move it down with your fingers. If you can't, it means that the VNT mechanism is gummed up and needs an overhaul. Don't be tempted to use the "oven cleaner" solution!

Basic setting procedure here:

5-Speed Electronic Manual Transmission (085) - Ross-Tech Wiki

wiki.ross-tech.com wiki.ross-tech.com

Follow to the letter and in the indicated order.

RAB
 
RAB said:
Check all the turbo pneumatic connections - at top left, looking from the front. They are easily disconnected.

Check the VNT actuator - with the engine off, you should be able to move it down with your fingers. If you can't, it means that the VNT mechanism is gummed up and needs an overhaul. Don't be tempted to use the "oven cleaner" solution!

Basic setting procedure here:

5-Speed Electronic Manual Transmission (085) - Ross-Tech Wiki

wiki.ross-tech.com wiki.ross-tech.com

Follow to the letter and in the indicated order.

RAB
Click to expand...
Top tips on here!

BTW, a mechanic suspected oil leak in the hydraulics system and I got a bottle of Automatic transmission fluid(ATF fully syntetic I think) with the car and was told I should use that in the hydraulics reservoir. Is this ok to use in that system?I think they already have put some in.

Should I get something else when I go to get a 24mm spanner later today?
 
Yes, buy some VW power steering oil, G002000 I believe. ATF probably not suitable.

RAB
 
RAB said:
Yes, buy some VW power steering oil, G002000 I believe. ATF probably not suitable.

RAB
Click to expand...
Ok, good to know.... I am just afraid of blending the two.... Since I got the bottle from them I have a feeling there is some in there. Is there an easy way to drain the system and fill it up again? ....I am sorry for bothering you with all these questions but this information is gold for me now!
 
Or maybe I should just suck out whats in the reservoir and put the VW power steering oil, G002000 in.
 
If you don't have a copy of VCDS or similar and the cable for it, I'd go and order one now. You will need it.
You will also face the prospect that many mechanics have minimal idea as to what's in front of them, still less understand how to fix it. I'd make friends with RAB on here, and Andre (Phoenix A2), Mankmil, DerweisseA2 and Janihani over on the German forum. They are extremely knowledgeable on the 1.2 and if they can't fix it you have a big problem. If I remember correctly, John was going to ship his A2 from Tromso through to Hamburg because that was the next knowledgeable mechanic who was prepared to deal with the car...

The GGE must be followed to the letter and with the correct values in the potentiometers and voltages or things will not work correctly. It will highlight anything going wrong and may not run through as a result.

- Bret
 
I have had a similar(ish) problem last summer. The weather was over 25c from April to the end of the summer in Norway and the constant dry heat made lost of old hoses and other parts more prone to misbehaving. I had the exhaust hose hop of the engine as the o-ring became too loose (awful sound and loss of power really gets you worried and it was such a relief to find a single screw to be the fix), squeaking from recently replace front suspension and whilst on the way to a specialist in Holland (to check the suspension) various gear change issues.

The suspension noise was purely due to it all being so dry and was cured with a little extra grease on the rubber in the mount.

But on the way down my car started to have issues. First around 20 mins from home the car locked into 5th gear and would not change down. I pulled to the side of the road turned off the engine and all was fine when it turned back on. I therefore took the ferry to Germany without further investigation.

The drive through Germany was hell as the gearbox would randomly (usually after around 20 mins) be unable to change down from 5th. On coming to traffic or using junctions this was very tricky. I carried on as I was nearing the workshop.

Fro. South of Hamburg I tried driving using the tiptronic but it did not entirely solve the issue and I had to switch the engine on and off around 3 times in the last 5km to the workshop. By the time I was in the last 100km I was fairly confident that I would not suffer a catastrophic failure and that even so the money saved in towing a shorter distance and coming to an expert on the 3l rather than a main dealer/random garage was worth the risk...

The pump for the actuator also seemed to run for longer than usual. At a petrol station opened the bonnet and saw that the hydraulic fluid was slightly low but there was no other obvious fault and VCDS showed no errors.

The problem turned out to be a tiny leak in the hose to the actuator. The new hose was around €70 but it solved an odd fault completely. The mechanic showed e that if there is no fluid the engine will not start and that the tolerances between working properly and having issues are relatively small.

If you have the system removed from the car anyway it should be say to find a small leak if you set the hoses and components on a sheet of paper or such where the fluid will leave a clearly visible stain.

I have also found with the A2 1.2tdi that you can quickly look for bigger more expensive problems in what is fundamentally a very well designed albeit complex system. The majority of problems I have had have been from what are now quite old well used hoses.

Hopefully my rambling was of some help!
 
John L even though hose has fixed issue, longer term it may have bent selector fork. When you come to replace gearbox bearings then ensure forks are straight.
 
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