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Mechatronics...


RedRobin
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A few weeks ago I was accelerating in DSG D-mode from a roundabout, greasy road so nothing heavy, and as she changed gear my Millteks delivered the loudest POP!! I'd ever heard. My initial thought was that it was the turbo, not breaking, but dumping a huge fart. But then I found that the revs weren't changing and the gears weren't continuing to shift and that the whole gear display P-S was all lit up. I treated it like a tyre blow out and just indicated and coasted to a layby. I put the floor shift in N and then back in D but she wouldn't move and the display all lit up again as all gears/modes selected.

I thought about the sound I had heard and that it didn't sound as if anything mechanical had broken. In passing I thought how pleased I was that my Millteks had allowed me to hear so much detail. I was on my way to meet up with Ray West at Thruxton and naturally was looking forward to it, but before phoning I decided to switch off the ignition, wait a moment or two and start up afresh....Afterall, everything is managed by a computer and often a re-boot will sort it out. Sure enough everything worked as if nothing had happened so I gently went on my way listening to every sound and breath, spent a good day with Ray and opened her up a bit more on my journey back home.

100 miles or so later and all was still as normal and still is more than 1,000 miles later. I reported it to my dealer and they ran a full diagnosis the next day. DSG fault code was beyond their understanding so I wrote up a report and it was sent to VW Technical. Results came back today: Mechatronic Unit plus gasket etc etc going to be replaced on Monday. So what is a Mechatronic Unit?

Mechatronics refers to a hydraulic/electronic transmission control process. Depending on the situation and the driver's requirements (gearshift process), it determines which ratio is currently active and which gear is pre-selected. This totally matches what Ray and I had thought was likely - A kind of clash as two cogs tried to go through the same single door at once - A hiccup which caused the computer to throw up its hands and be confused.

I'll find out more on Monday and keep you posted.

Does this put me off DSG? - No way!!

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You know....its funny you should mention this because there were several occassions when I had the M3 that I experienced quite a loud knock, the kind of knock you get when a feck off great lump of rock might hit your windscreen and scare the living crap out of you. But I never ever found out what caused it, but I experienced it several times. Not sure if MrMe can remember me remarking on it, but it usually happened when SMG was in auto then switched to manual mode and it would ALWAYS happen once SMG had been in auto mode on a long run. Then as I manually went down the gears to a halt, in 1st gear as the car was about to stop, this bloody loud knock and it did shock you when you heard it. I checked other forums to try and figure out what this was but never ever did figure it out. And as usual the dealer never had a fecking clue either. But it was definately connected with gear change having swapped from auto to manual. WIERD!!

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If you put the search term "DSG Mechatronics" into google it comes up with a few hits for example this quote from a Volkswagen AG article relating to the DSG box:

[ QUOTE ]

Two wet plate clutches, each with two input and output shafts, are responsible for this in addition to the intelligent hydraulic and electronic gearbox control (mechatronics). This bond makes it possible for the next idling gear to be on permanent stand-by until activation. And lightning fast.

[/ QUOTE ]

My first Golf Gti didn't get through PDI due to a fault relating to the Mechatronics module. Eventually VW re-ordered a replacement car from the factory as the dealer couldn't fix it.

I haven't experienced the POP noise you describe but on the odd occasion I've put it into D or R, no gear has engaged and the whole gear PNRD12... display flashes. This hasn't happened for a while though.

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Hi Melchior, it sounds as if it would be wise for you to get your dealer to run a full diagnosis and see if any fault code is thrown up. Each event should get logged by the car's system. How many times over what time period is "the odd occasion"?

As your first car had to be replaced and your second car does it on the odd occasion, sounds a real bummer. If my car had to be replaced I wonder if VW would also cover the costs of fitting my Millteks and suspension and moving my aftermarket SatNav etc??!! I don't understand why the dealer couldn't fix it - the whole module can be replaced, or was your dealer not a VW one?

When was each of your cars built?

Sorry for all the questions 169144-ok.gif

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Hi Red,

The issue of not being able to engage a gear and the gear display flashing has happened on three occasions, all around the 2-4k miles mark. Its a MY06 car buily in June 05 and has about 8k on the clock now. I'll ask the dealer to check the codes next time I'm in.

The first car was a MY05 car built around Feb / March 05. Initially they said the fault code related to the mechatronics module. The VW dealer did replace the Gearbox Computer module (not sure if that's the same as the mechatronics unit), but it didn't fix the fault. It was at this point I walked away from the car and never found out what the fix was (The first car was still at the dealers when I picked the replacement up.). I couldn't understand why the dealer couldn't fix it either.

confused.gif

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Thanks for that very useful info, Melchior 169144-ok.gif.

Mine's MY06 built July 05....happened only once so far at about 6K miles and am now at nearly 8K. I really hope that my dealer is going to be able to sort the fault. I'm not sure but I don't think that the "Gearbox Computer module" is the same thing....The Mechatronic Unit has been named as such since Audi DSG started. The Gearbox Computer sounds as if it's a different unit and if the actual fault is in the Mechatronic Unit then it might explain why your dealer has been barking up the wrong tree!

My dealership has a major accident repair centre and is very well versed and equipped in healing cars. I'll keep you informed.

Anyone got a technical pdf file on the whole DSG system?

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Melchior, thanks to mikemod's pdf I can confirm that we are right in thinking that the Mechatronic Module and the Gearbox Computer are indeed quite different and independent components....Fecking dealers!

To quote from the pdf:

"The mechatronic module determines and manages data for controlling the clutches, input and output shafts, cooling, gear selection, pressures, as well as various malfunction security levels. Five modulation valves, five shift valves, and numerous hydraulic slider valves enable transmission control. A connector allows the transfer of gearbox data from the control unit to the vehicle onboard network, and information from the vehicle and engine flow through the interface in the other direction to the gearbox computer".

Guess what? - The Mechatronic unit is located in oil inside the DSG and can withstand temperatures up to 140C. I wonder how long I will be without my car for?

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Thanks, petsy but my car is currently running very well....It's possible that the mechatronics fault could happen at any time so best to get fixed under warranty....Thank goodness I haven't re-mapped!

Talking of re-mapping DSG version GTIs, the DSG box is designed to take no more than 258 lb ft of torque capacity.

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[ QUOTE ]

[ QUOTE ]

Talking of re-mapping DSG version GTIs, the DSG box is designed to take no more than 258 lb ft of torque capacity.

[/ QUOTE ]

Arse, somebody better tell BBR then laugh.gif

[/ QUOTE ]

And VW....aren't they using or planning to use DSG with higher output engines. Whats 258 lb ft in Nm?

My dealer reckons there is no difference between the MTM performance output between manual and DSG and that neither have caused any problem related to the ECU remap.

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[ QUOTE ]

[ QUOTE ]

[ QUOTE ]

Talking of re-mapping DSG version GTIs, the DSG box is designed to take no more than 258 lb ft of torque capacity.

[/ QUOTE ]

Arse, somebody better tell BBR then laugh.gif

[/ QUOTE ]

And VW....aren't they using or planning to use DSG with higher output engines. Whats 258 lb ft in Nm?

My dealer reckons there is no difference between the MTM performance output between manual and DSG and that neither have caused any problem related to the ECU remap.

[/ QUOTE ]

258 lb ft equates to 350 Nm.

I wouldn't want to put more torque than that through my DSG box.

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The mtm upgrade available in at dealers in NZ (and warranted by them also) gives 245hp and 355Nm. I wouldn't be too worried as I'm sure VW have engineered the thing so it can be easily dropped into models such as the new S3 without having completely different DSG boxes for each model.

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Jono is right - The DSG box is manufactured separately in Kassel at the rate of 1,000 per day and is applied as appropriate across the vehicle range.

MTM, represented by QST in the UK, don't seem to think (as far as I can tell) there's any difference in tuning DSG and Manual GTIs but most of the other tuners do!

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The fault in my Mechatronics Module was a failed Pressure Valve, though it has not been eveident in the last 2,000 miles (approx).

Car should be ready for me tomorrow....I've got a Mk4 Golf TDI loaner which drives like she's a 1-litre marsh-mallow with no brakes. Does the "T" really stand for Turbo? - I can't feel or even hear a turbo? I don't care how many zillion miles she does to the gallon, I'd give up driving if I had to suffer this one every day!

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New Mechatronics Module replaced under warranty. Software 'pressure valve' had failed/hiccupped once. Work took one and a half days and with close liaison with VW Technical. She feels slightly different to drive after the necessary reset - I'll post a new topic soon called "Learning your Driving Style".

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  • 7 months later...

Interesting thread Robin. I shall enjoy reading the DSG pdf sometime. grin.gif

Glad yours is all fixed now 169144-ok.gif

BTW with regard DSG and torque limits i'm sure I have read on here that it's not the physical gears that are weak just that the controller needs reprogramming. Although obviously there will be a limit when you start to strip gears !

Notice they dont fit it in any Touareg .... especially the V10 version ! grin.gif

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Robin you are right it is a Dual Clutch system but the one in the Veyron is made by Ricardo who make the F1 'boxes and their factory is around the corner from me.

Here's a link to an award they won for it

I suspect the fact it has two clutches and some gears is where the similarity stops with the Golf version grin.gif

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