MK4 Jetta Autotragic Woes Need Help

[D911]

So my girlfriends car started acting up, it seemed to go into a limp mode, and then it resolved itself and now it seems a little more permanent. I'm thinking something was loose and now its broke, what that something is, I have no idea. I am not the best with automatics. Now I have a friend with a VCDS who was helpful enough to give the car a scan this is the result:

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Chassis Type: 9M (9M - VW Jetta IV (1998 > 2014))
Scan: 01 02 03 08 09 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57
75 76


VIN: 3VWSB29M42M016784 Mileage: 117080km/72750miles
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Address 02: Auto Trans Labels: 01M-927-733.lbl
Part No: 01M 927 733 KQ
Component: AG4 Getriebe 01M 4892
Coding: 00000
Shop #: WSC 00000
VCID: 89171B82B39C7F564C9-0962

1 Fault Found:
00264 - Solenoid Valve 4 (N91)
36-00 - Open Circuit


N91 solenoid, I gave that the Ohm (resistance) test that was reccomended on vortex, came out with a reading of ~7.4ohms, and the acceptable values are somewhere closer to 5 ohms. I'm not sure if that is out enough to be worrying, or if my problem lies elsewhere. I gave a cursory check to the wiring that connects the TCM to the transmission, and it appeared to be in good order. I'm unsure of how to proceed, or what I need to look at next. Any transmission guru's want to help me out here?

EDIT: the initial measurement was when the car was hot. I rechecked after the car cooled down closer to the spec temperature, everything seems a lot closer. Does this mean that my solenoids are okay? What am I looking for if i am to trace the external wiring? Could it the the TCM..? Any way to do testing on that?

EV1 - 72.6
EV2 - 63.3
EV3 - 62.4
EV4 - 5.2
EV5 - 64.1
EV6 - 5.3
EV7 - Forgot to check lol.
TFT - 175 600

the spec at 20 deg C

EV1 - 55 to 65
EV2 - 55 to 65
EV3 - 55 to 65
EV4 - 4.5 to 5.1
EV5 - 55 to 65
EV6 - 4.5 to 5.1
EV7 - 55 to 65
TFT - 190 to 200k

[witchcraftz]

Re: MK4 Jetta Autotragic Woes Need Help

N91 is the TCC modulating valve. If it fails, the car will not lock the clutch and the engine will run faster (no "overdrive").

N91 can be serviced without splitting the transmission apart. Be sure there is no external electrical fault first though. 09A solenoids can be ordered from VW or probably anywhere. It's a popular AT that's used by many brands. The VW P/N is 09A927331E. It is supposed to come with new o-rings.

You have classic symptoms of sticking solenoid. You should change them all as a set.
There are bunches of folks in the following thread who fixed "delayed upshift cold" with solenoids.

forums.fourtitude.com/showthread.php?4188370-02-1.8T-Jetta-not-shifting-gears-from-1st-when-cold&

[D911]

Re: MK4 Jetta Autotragic Woes Need Help

forums.fourtitude.com/showthread.php?4188370-02-1.8T-Jetta-not-shifting-gears-from-1st-when-cold&

Thanks for the link Witchcraftz. I did end up resolving the problem though, with perhaps not the most ideal solution.

For anyone who happens upon this post, here's what I did:

I ohm tested the solenoids through the transmission case harness, and everything tested out fine.. I looked over the external wiring harness to the TCM and it all seemed to be in order, no pinched wires, broken cables, etc. So with nothing else to go on, I trusted the scan, and decided I needed to replace the N91 solenoid as the first step, I called some stealerships if i could try and get just the solenoid. They claimed that they could only order the whole valve body, and that wasn't going to fly since they wanted 1100 (!!) plus core deposit of 200 something. Noped out of that option real quick. I even tried to give them the part numbers I found from a different source but same # you found for me, no dice.

Given I know nothing about where to procure transmission parts like that, next best option for new solenoid would be online. Most inexpensive was around 60 with shipping, but my girl needs the car sooner than later, and shipping would take up to 3 weeks.

So I went to the ol' Pick'n'Pull and looked all over for an autotrans MK4 car, none were found, but luckily I remembered that the Mk3s used the same transmission. So I cracked open a trans of a MK3 Jetta and took the whole valve body (incase I needed other solenoids, or anything else). Gave the new solenoids a quick ohm test in the yard before packing it up, 4.2 Ohms, right like it should, but not super promising, since the supposed broken one is also reading out the same. Of course I never bothered to look up how else to test these solenoids, in retrospect, I probably should have. Home time.

With the new solenoid in hand. I opened up the girl's car, drained the fluid, pulled the pan, and following the tips on kansascitytdi.com, I very very very carefully took the plug off the solenoid I needed to replace, and put in the new one. Serious emphasis on the careful part, the plugs are pretty delicate and are prone to breaking, I gave no shits on the one I took off in the junkers and broke all the clips, but I spent a solid 40 minutes on the actual car to get the one plug off, was being super cautious, a new harness is pretty pricey. Once you have it leveraged the right way, it pops right out, no need to be giving it too much force.

Throwing everything back together, I followed some DIY's for replacing trans fluid, I ended up using Mobil1 3309 (I think its called), as it meets the VW spec G05 bblahlabahl, and I didnt want to pay $30/L for the OEM stuff. The DIYs out there for the trans fluid change make it sound like its the hardest thing of all time. Compared with the damned clips, it was a cake walk.

With everything bolted up, and filled to the proper levels, the car was ready to go, I did the TCM reset procedure:

Ign. ON
Gas Pedal down for 15+ sec
Ign OFF.
Release Gas Pedal
Touching nothing, turn car on.

Went for a drive... and ****, car still drives like ****, still running in limp...CEL still on...Anger grows and then I light bulbed. I need to clear that code first...derp.

Got my handy dandy 30 dollar OBD2 Scanner, found the code, cleared it, went for another drive. CEL stayed off (unlike before, it would immediately return after being cleared by my friends VCDS), repair was a success!! Car drives like it should, if not actually a bit better, the new fluid at proper level definitely smoothed out the shifts. The original trans fluid wasn't even too bad, comparing with what I've seen online, filled with metal chunks and very dark/opaque.

TL;DR fixed the problem, with a used part, lets hope that doesn't bite me later. Also remember to clear codes before going for a victory lap.

[witchcraftz]

Re: MK4 Jetta Autotragic Woes Need Help

Glad you got it fixed. Good info about the MK3 transmission, can you post the exact model of the MK3 transmission that you got it from?.

[D911]

Re: MK4 Jetta Autotragic Woes Need Help

Glad you got it fixed. Good info about the MK3 transmission, can you post the exact model of the MK3 transmission that you got it from?.

Thanks. I am too.

Its the same transmission as the 4 Speed Auto's in the MK4s. It's the 01M transmission. I forget where I read that info exactly, but it certainly came in handy when all the MK4s in the yard were manual. I am also pretty certain that the solenoids in the 09a, 5 speed auto in the MK4s (?) use the same set of solenoids, though they are mounted completely differently.

I'm still a little worried that the used part I threw in there is just bound for failure again. Knock on wood it lasts forever though! haha.