VR6 Auto Problem - Help save a Corrado!

[dief 0]

Hi all, the knowledge on this forum has helped me a number of times through the early part of my corrado ownership but this is my actual first post!

 

Calling all auto gearbox owners really, reading previous threads I think this problem has come up with others (but I can't find one with a solution - not looking good!).

 

My auto box has taken on a life of its own and it basically, picks and chooses when it wants to change up to 4th, if at all. Totally intermittant, works fine 90% of the time, so garages don't know how to go about tracking the fault down.

 

- It started with a "squawk" changing from 3rd to 4th.

- Then, v. intermittant - no kick down

- Then it became an increase in revs during a longer change up to 4th

- Then sometimes it wouldn't change up to 4th at all.

- Finally it went into limp home mode (I assume) 3rd and reverse only. Though then fine after being left for a while

- Now sometimes it'll even switch down from 3rd to second, limiting the car to about 45mph (not good on 2 recent motorway trips!!)

 

Taken it to a gearbox place by me (Hardy Eng. off M25 Kingston) who don't seem to think the gearbox is the main cause and point the finger at something electrical (wiring, ecu, sensor connections etc). Seem to know their stuff and didn't want to start running up bills by just replacing random parts (compare and contrast - local VW dealership!).

 

Code reading turned up these same codes twice:

- 00518 Throttle Pos Sensor

- 00652 Tran Range Controller

- 00638 Eng/Trans. Connection 2 No Signal

 

There was a solenoid code once but this hasn't repeated whilst the problems have gotten more frequent.

 

Anyone had similar and found a solution?

 

90% of the time it drives fine, and always goes back to normal when left after an 'incident', but it's let me down twice recently on a motorway 200 miles from home not wanting to go above 2nd gear and limited to 4,000rpm.

 

Unfortunately, though I'm willing to forgive my corrado almost anything, others think this is proof of it's "impracticality" and without a solution it's living on borrowed time... :help:

[Storm 0]

Try a gearbox flush and new oil. If push comes to shove then see the link in my sig. :(

[fla 9]

The 00518 and 00638 fault codes invariably come together.

 

Firstly, scan the tcm and clear te fault codes. Drive and rescan. If teh two codes above reappear then there are a few possibilities. Firstly replace te TPS (throttle position sensor) which affects gearchange. Cealr codes and rescan.

 

Then, replace your tranny fluid and filter (i've got a brief summary in my 'engine tapping noise thread, page 13 or 14 iirc) Get a good additive like Lubegard and add this to your oil.

 

You will need some time for it to circulate in the solenoids and the clutches

 

Still no joy then drop teh sump and you will see the solenoid pack and a 'ribbon' cable above it, see it this has any breaks in it. Also check the diode at the cable, an auto shop should be able to do something with it as its not available separately.

 

Still no luck, you will be looking at two more possible issues:

1. the solenoid pack will need tombe disassembled and thoroughly cleaned - its not much of a problem you just need to be careful.

2. the gearbox will need to be removed and refurbed, which means replacing the shims and clutch plates. there is also a bonded piston(s) which is used to operate the clutches and gearchange which may have gone hard hence causing shift issues.

 

Thats basically it. Try the fuid change and make sure to use some good quality ATF and definitely try the Lubegard. I will post some new pics of my filter later this evening so you cn see teh state of things.

 

Failing that, you can simply pull out the auto and put a manual in! Good luck and drop me a pm if you want to bounce any other ideas around.

[dief 0]

Seriously guys, many thanks for this!

 

Storm - changed the oil but no luck I'm afraid.

As for a Manual conversion? Maybe if I give up and look to sell, 'fraid I just can't live without my lazyman's gearbox anymore (particularly not in London - doubt my achilles could take it anymore!)

 

fla - wow, thanks a million for all this - a lot for me to be getting on with there. Much appreciated! :notworthy:

Having tried the clear codes/oil change (not sure about lubeguard as it was a garage)/rescan, I think something TPS related looks like my next step - have you had the same issue?

 

Only fear from elsewhere on the forum was that I read a couple of stories of people having gearboxes entirely reconditioned due to similar sounding 4th gear probs, only to be back in the garage a couple of months later for new ecus, new TPS etc. Might be a common combined mech/electrical prob?

 

Again, many thanks for all your help (and any more tips/pics greatly appreciated!)

[fla 9]

You're in London - whereabouts? There is a garage called Stephens Engineering on the North Circ, near to Bounds Green. You can give them a shout and get teh Lubegard from there. they're quite knowledgable too.

One of these days i want to get a shafted auto box, strip it down completely, identify any faults and rebuild it. There was one going for free a while back , i just didnt have teh time to pick it up.

[dief 0]

I'm in Kingston, SWLondon/Surrey - been using a garage called Hardy by ours which advertise as a gearbox specialist and seem to know their stuff and have been fair in warning me about how expensive it could get to track down the problem. I'm just a bit weary of handing it over with a 'fix it' mandate as, with it being intermittent (though def getting worse recently), I think I could easily run up hundreds through a standard diagnostic approach replacing oil/sensors/wiring/ecu one at a time and then find out it also needs a full recon!Was hoping that there might be a known common fault that a magic bullet could cure(!)

 

No answer to that I guess, in the long run I guess it's bite the bullet or so long corrado!

 

Many thanks for everything, really appreciate it.