DSG Leak at Electrical Connector

thecause17

Veteran Member
Joined
May 5, 2014
Location
Dover, DE
TDI
2010 Salsa Red TDi DSG
When I did my last oil change I noticed my car was leaking DSG fluid. After searching on here it seemed likely to be the filter o-ring so I went ahead and ordered one. I went to change it today and after removing the airbox it was apparent that wasn't the culprit. Here's a pic of where the fluid looks to be leaking from:



I cant figure out how to disconnect this connector. Can someone tell me how you do it? I'm not sure if I can even get the seal that's in that plug.
 

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
hear of it, haven't seen it.

The tab on the right side of the round connector, rotate it to the left about 90 degrees.
 

thecause17

Veteran Member
Joined
May 5, 2014
Location
Dover, DE
TDI
2010 Salsa Red TDi DSG
Yeah, I tried that, but it didn't want to give, and I didn't want to snap it off. It almost looks like it's not even in there straight, but I don't see how this type of plug would even allow that to happen.

As far as I know it's the connector for the mechatronic unit, and I can't seem to find where you can get the o-rings or connector separately. Can anyone confirm this?
 

wrenchman30

Veteran Member
Joined
Oct 1, 2007
Location
arkansas
TDI
2005.5 gray 2006 dark blue
whatever you do do not use silicone, use anerobic sealer, it appears to be a oil leak thru the plug and wiring not from around the wiring harness, have you recently serviced the transmission the vent is right there and if you overfilled it could blow out oil, clean the connector and recheck it later. If the wiring harness is passing oil thru the connector there isn't much to do but replace the harness inside the tranny. the sealer would be used around the oring at the mounting area not inside the harness where the wiring terminals are.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
The connector's seal is UNDER the M-unit cover, so stop messing around, you won't get to it easy.

Chances are, the vent may have seeped a little out, especially if the box was a bit overfilled.

I'd clean it all off, and see if it comes back in any short amount of time. I'm betting it won't. I'm betting what you are seeing in that pic is 150k+ miles of minor seepage, nothing I'd be too concerned with. Certainly not enough to dive into taking the front of the car off and pulling the M-unit cover off (which also has a seal that would need to be replaced).

If you like, wait until your DMF fails (it will, eventually) and you have to pull the trans out. THEN the M-unit cover will be super easy to reseal.
 

thecause17

Veteran Member
Joined
May 5, 2014
Location
Dover, DE
TDI
2010 Salsa Red TDi DSG
I'd clean it all off, and see if it comes back in any short amount of time. I'm betting it won't. I'm betting what you are seeing in that pic is 150k+ miles of minor seepage, nothing I'd be too concerned with. Certainly not enough to dive into taking the front of the car off and pulling the M-unit cover off (which also has a seal that would need to be replaced).
I will clean it off and see what happens. The car has 70k miles and everything has been bone dry up to this point. The DSG was serviced by the dealer about 20k miles ago and I've never seen anything in the last couple oil changes before this. To me it seems to be a little more than seepage, since the belly pan is wet, but I will clean it up and see where it goes from there.
 

JimmyFnB

New member
Joined
Apr 22, 2015
Location
NJ
TDI
2009 Jetta Sportwagen TDI
I have a similar issue with my 2009 Sportwagen TDI, but I believe it is also causing a communication issue between the TCM and ECM. Usually, this happens at highway speed. The traction control light comes on, and the engine revs up, as if I had shifted to neutral, but the PRNDS indicator on the MFD disappears as well. I generally solve it by shifting into Neutral and restarting until the communication is restored. After it occurs twice, the MIL comes on and a code of U0101 is stored. The MIL goes out if I have a few successful drives.

The problem started last October, a week or two after I had the 120k service done including the DSG service at the dealer. I brought it back and they said they found corrosion on the grounds to the TCM. They cleaned off $200 worth of corrosion, and the problem seemed to go away for a month or two. It started happening again early this year, and I did a little looking myself. I noticed that there was fluid in the connector on the transmission below the airbox. I cleaned it out, and the problem went away for another month or two, now it is back, and there is indeed more fluid in the connector (see pictures). It seems like the fluid is pushing into the connector from inside the transmission. I am now at about 135k.

Has anyone had a similar issue in connection to a fluid leak at this harness? Am I in for a new mechatronic or just replacing a seal? Is this an overfilling issue?

Thanks,
Jim
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
If ATF is getting INTO the connector, chances are that there is a breach in the pins in the connector itself in the transmission, which is, unfortunately, part of the M-unit itself.

If the seal under the cover leaked, it would most likely just manifest itself as a small external leak, but would be unlikely to actually get into the connector itself.

However, ATF is non-conductive, so that in itself should not cause any electrical problems. Much of the transmission's internal wiring is all exposed to ATF.

I would want to see what DTC(s) came from this event that were stored in the M-unit. Since cleaning this connector does seem to help your problem for a while, though, it would suggest that the problem does indeed lay in this area.
 

JimmyFnB

New member
Joined
Apr 22, 2015
Location
NJ
TDI
2009 Jetta Sportwagen TDI
The only DTC I've gotten is U0101. Unfortunately, I don't have a means to read DTCs from the Mechatronic unit.

I took a few pics, similar angle to thecause17's, but with the connector unplugged and you can see the fluid in the port. The fluid in the connector looks fairly clean, so I assume it is leaking into the connector from inside the trans. I assume I need more posts before I can attach pics.

I understand your comment on ATF being non-conductive, but if that is the case and it gets between the pins of the connector, that means the pins may not make contact or make intermittent contact.

Cleaning the fluid out seemed to help for a few weeks to a month when I did it back in January. I cleaned it again yesterday, and on a short drive today had no issue (versus multiple occurrences yesterday and earlier this week).
 
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MonsterTDI09

TDIClub Enthusiast, Veteran Member
Joined
Jul 3, 2009
Location
NoVa/NJ
TDI
2010 Jetta DSG/ up keep on 2009 Jetta DSG 2006 Jetta Pag 2 in North SEA Green
Did you have the recall done for the DSG temperature sensor?
 

JimmyFnB

New member
Joined
Apr 22, 2015
Location
NJ
TDI
2009 Jetta Sportwagen TDI
Did you have the recall done for the DSG temperature sensor?
As I remember, my VIN was not a part of it. I have read some posts about it and some of the symptoms are extremely similar. I bought my 2009 in July/August 2009, so I'd have to check the build date, but it is clearly before August 2009 (and probably well before as I know it was at the dealer for a while). I've seen varying information online as to what dates the temp sensor recall applied to, NHTSA says 9/2008 to 8/2009 but other sites seem to say it was more limited.

From the VW site, there is one open Service campaign, 2306 for an ECM upgrade related to emissions. Not sure if that site would list everything that ever applied to the car or just current.
 

BuzzKen

Vendor , w/Business number
Joined
May 16, 2011
Location
Markham, Ontario
TDI
'10 Touareg TDI, '09 335D, '10 X5D
This leak is not around the connector(oring seal), it is bleeding out throught the pins. I have seen this twice and without disassembling the mechatronics unit myself, I'm not sure what/if the fix would be.
 

Krash

New member
Joined
May 27, 2015
Location
Tennessee
TDI
2010 CUP Edition
I appear to have the same problem with oil leaking out of the electrical connector. Noticed it at my 90K oil change, I have cleaned it it up twice and it appears to be getting worse at 93K now.

Wondering if anyone has had this issue repaired? If so what did it require? Can it be resealed or did it require a complete Mechatronics module replacement?






Thank you


K.
 
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JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
I have picked up on another one of these situations on a 2010 JSW.
The fluid is leaking from a vent in the multi-pin connector. It is a tiny hole in the inner circle of the void where there are no pins. It looks like a small brass tube that is half-covered by the outer ring of plastic. (sorry, no paint program available to circle it ).

This picture is of a different mechatronic connector that is out of the car so that the connector vent is in plain view.



located about 3:15 o'clock on the inner circle of the void...

I pulled the tranny vent cap off and applied a little compressed air to force the issue. It weeps a bit of fluid when I do that. The pins do not have the leak.

The place that changed the fluid (118K) last sold the customer 6 quarts or liters...it does not specify in the work order but, probably liters but, who know how much of that was the final level of fluid.
I drained right about 4 liters of fluid from the trans just now and it is 34K later.

There does not seem to be any seepage around the case vent but the front of the cover and underneath the tranny is drizzled with fluid.

The dealer wanted to replace the mechatronic and maybe the harness at near $5000!!!

Has anyone ripped one of these trashed mech's apart?
It would be handy to know how the fluid got pushed into a gasket-sealed connector with enough force to leak out the back side onto the trans.
 
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JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
I assume that the connector vent is there to relieve air pressure as you engage the harness connector.
Makes me wonder...If the harness connector o-ring was really sealing, would the the fluid still ooze out of there?
 

wilber123

New member
Joined
Apr 12, 2016
Location
australia
TDI
mk5
When I did my last oil change I noticed my car was leaking DSG fluid. After searching on here it seemed likely to be the filter o-ring so I went ahead and ordered one. I went to change it today and after removing the airbox it was apparent that wasn't the culprit. Here's a pic of where the fluid looks to be leaking from:



I cant figure out how to disconnect this connector. Can someone tell me how you do it? I'm not sure if I can even get the seal that's in that plug.

Have the same probleme with my dsg. Was wondering if you have found a fix for this probleme.cheers
 

edge130

Veteran Member
Joined
Jan 18, 2009
Location
northern NJ
TDI
Wife's 2009 Jetta TDI sedan (2009 - 2017)
Warranty?

Would this be possibly covered by vw warranty extension on the DSG transmission?
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
For the record...



I ran into this again today on a 2006 Jetta.
It also has codes for the following:



17106 - Transmission Output Speed Sensor (G195)
P0722 - 000 - No Signal - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 255
Reset counter: 37
Mileage: 373867 km
Time Indication: 0

18201 - Transmission Output Speed Sensor 2 (G196)
P1793 - 000 - No Signal - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 255
Reset counter: 37
Mileage: 373867 km
Time Indication: 0


It rather resembles the symptoms mentioned earlier with the engine free-revving through a shift until it figures out what to do about it.
I don't know that the fluid issue has anything to do with the speed sensor codes.


Any solutions out there yet?
 

phantom1260

Veteran Member
Joined
Aug 15, 2017
Location
Brampton, Ontario
TDI
2010 Jetta TDI
Just got back from the dealer and as per the pictures they provided I have a leak in the Mechatronic unit connector as well.

This occurred a couple of days after I had the DSG service completed at the dealer. They cleaned it up and reconnected it but on my way home from the dealer the transmission faulted out again and I was limited to 1 gear.

No error code yet this time but before I went to the dealer I pulled Code P0746. They provided me with the code P1814 at the dealership.

Was anybody ever able to solve this or am I looking at having to replace the entire Mechatronic over this? Is there a o-ring or any sealant that can be applied?




 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Somehow I doubt that the fluid coming out of the connector is causing a fault for the codes. The mechatronic unit is submerged in the fluid...electrical connections and all.

It can make a mess, though.
I have witnessed this connector leakage on a few DSGs where the car runs completely fine. I think the code in my previous post was coincidental.
 

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
I've seen it a ton of times as well, our 2010 is leaking as well. I have a theory that the DSG fill procedure over-fills it compared to the original fill by a small amount. I'm not sure I've seen a low mile DSG trans leaking from that connector.
 

phantom1260

Veteran Member
Joined
Aug 15, 2017
Location
Brampton, Ontario
TDI
2010 Jetta TDI
Somehow I doubt that the fluid coming out of the connector is causing a fault for the codes. The mechatronic unit is submerged in the fluid...electrical connections and all.

It can make a mess, though.
I have witnessed this connector leakage on a few DSGs where the car runs completely fine. I think the code in my previous post was coincidental.
I'm leaning towards too much fluid leaking out and causing a fault in the N215 solenoid from the fluid being too low. This would make sense since the car was okay for 3 days of driving after the service. Then perhaps when the fluid got too low it started causing errors.

When I replaced the o-rings the connector area seemed to be dry on the outside where the o-rings sit. It was only leaking on the inside where the pins are.

I tested all the solenoids for resistance and none of them jumped out to be faulty.
 

Jbwoo

Active member
Joined
Oct 28, 2018
Location
Kingston WA
TDI
15 GSW 06 Jetta BRM
Need to seal inside the connector where the pins are. Glue, JB weld, or a new connector. The o-ring obviously doesn't.
 

Jbwoo

Active member
Joined
Oct 28, 2018
Location
Kingston WA
TDI
15 GSW 06 Jetta BRM
No, the problem is fluid getting into the back of the connector and then between the connections. Dielectric grease is what I use for anti corrosion.
 

Toadusmodus

New member
Joined
Jan 8, 2020
Location
East Sussex
TDI
Octavia
Did you ever find a fix for this problem, as I have the same issue, loads of oil in this plug = no communication between gearbox and ECU?
 

phantom1260

Veteran Member
Joined
Aug 15, 2017
Location
Brampton, Ontario
TDI
2010 Jetta TDI
Sorry I haven't found a fix yet. I've parked the car for now.

Things I've done so far:

  • Rechecked the fluid level
  • Replaced the o-rings on the mechatronic connector
  • Cleaned the connector.
  • Replaced the mechatronic cover gasket
  • Replaced N215 Solenoid
  • Cleaned Ground connection under battery tray.

I'm still not 100% convinced the oil in the connector is causing the fault.

I've parked the car for now but I've been able to move it out of the garage when needed without it throwing an error.

I'm sure if I were to let the car warm up the error would come back.

Wondering if its related to the bad DMF but I don't see sense in replacing the DMF if the mechatronic is actually at fault.

I will probably continue to diagnose once the weather gets better. If I'm to replace the DMF I might as well just put in a used DSG at that time since I would be removing the transmission anyways.
 
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