Still Ironing out the Kinks on my new Purchase

Simply need new trans fluid, or something more sinister?

Recently picked up a 2000 Golf TDI automatic.
Broken coolant flange and transmission in 'limp mode' is all that was said.
Replaced coolant flange (URO parts is a savior) and drove home.
Put it in D, and it started off in 2nd gear, shifted hard to 3rd at 4k rpm, and shifted hard to 4th at 4k rpm. No OD.
Ok.
I replaced G68 sensor. Now has first gear and OD. Still shifting a bit high and still a bit rough.
No power in low RPM. Takes off very sluggish. When accelerating from 0, it pulls weakly until 1/2 throttle. Anymore throttle and it falls flat. When at 3k+ RPM, it pulls quite nicely.
When slowing down from 55+mph, it will downshift (on its own) and start to engine brake. Does it anywhere from ~37-50mph. Seems for some reason the TC is locking up on the downshift.
When in D, above the ~55mph mark, and just coasting, the RPM will settle at ~2k. When I bump it into N, it settles to 850.
In my experience, most of these symptoms point to low trans fluid, but I wanted to run it by here first.
Thanks for the input

Any ideas?

You don't mention the mileage.

I'd start by pulling the pan and replacing the filter.

You will find the 01M is not well thought of here. Mine has 170k and is doing ok.

KLXD said:

You don't mention the mileage.

I'd start by pulling the pan and replacing the filter.

You will find the 01M is not well thought of here. Mine has 170k and is doing ok.

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I can understand. I would definitely prefer the 5 speed. Seems kinda slushy. But I'd rather fix it if it's fixable than just immediately trash it.

Car has 153k on it.
I just want to know the next step in diagnosing the car.

Takes off very sluggish. Has no power below 2k rpm. Shifts rough, and at 3500-4000 rpm.

Drives much better if manually shifted into 1st then 2nd.

Low trans fluid or is this a bigger problem? How should I proceed in diagnosis?

Search up threads by CoolAirVw.

He repairs 01M's and posted a series of threads on them.

KLXD said:

Search up threads by CoolAirVw.
He repairs 01M's and posted a series of threads on them.

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Thank you very much for pointing me in a helpful direction. I saw his name on some threads I searched previously, but I will look more specifically at his posts.
I checked the codes again on a semi-professional scanner (Launch CRP123).
I got a bunch! I didn't expect this many, but I also haven't cleared them in a while so who knows
I put about 100 miles on the car since I changed the G68 sensor.
It still showed current P0722 - output speed sensor no signal. Also showed pending P0722
Pending P0730 - incorrect gear ratio
Pending P0725 - engine speed input circuit
Pending P1850 - a VW specific code labeled by my scanner as "Data-Bus Powertrain Missing Message from Engine Contr."
Pending P1857 - a VW specific code labeled as "Load Signal Error Message from Engine Contr."
Pretty interesting stuff. This is starting to point to a lot more than the transmission.
I've tried to search for threads involving these codes, but the other people's symptoms don't really fit mine. One result pointed to the 109 relay being faulty, but my car starts, runs, and shuts off fine.
The 700 codes point to bad speed sensors, but I just replaced the G68, things got better, and my speedometer and tachometer work perfectly.
The 1800s codes are a bit worrisome as they point to ECM issues.
Any input here?

Did you clear the codes? I would clear and see what comes back.

G38 sensor. Also, service the trans with filter and new proper fluid. See just how bad it looks in the pan and filter. Will need approx. 3.5 quarts but fluid level needs to be checked with computer program.

Does this transmission shift "manually?"

What Casey said.

Lotta times there are codes stored due to a low battery or some such that aren't really valid.

casey823 said:

Did you clear the codes? I would clear and see what comes back.

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I do not believe I specifically cleared the codes after read them prior to G68 replacement.
But I did have the battery removed for 2 hours while replacing the G68 sensor. Not sure if these cars are the type to reset ECU while battery is removed or not.
My E46 BMW is the only car I've come across that actually stores CEL codes when the battery is moved. Maybe it's another thing that German car makers have in common?

Prairieview said:

G38 sensor. Also, service the trans with filter and new proper fluid. See just how bad it looks in the pan and filter. Will need approx. 3.5 quarts but fluid level needs to be checked with computer program.
Does this transmission shift "manually?"

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Transmission shifts beautifully manually. Let me re-confirm tonight as I've only manually shifted from 1-2 about twice. I'll go all the way through manually and observe the power band better.

So right now you recommend throwing a new G38 sensor at it? and new fluid/filter?

KLXD said:

What Casey said.
Lotta times there are codes stored due to a low battery or some such that aren't really valid.

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Battery is about 10 months old, and very strong. As I said above, I did remove the battery when replacing G68, but don't know if that would reset the codes.


Thanks again for the help!

I drove it again. Except for slightly harsh shifting, the trans actually seems to be functioning properly. It almost seems like the more I drive it the better it gets. When in D, it shifts through all the gears at reasonable RPM points. I don’t feel any TC lock up, but I’m assuming it does as it sits at 2600rpm at 70mph.

Aside from the harsh shifting, the only other complaint in the transmission department is that it does that weird downshift engine braking thing when going into 3rd when slowing down. It also kicks down into a lower gear when pressing harder on the accelerator. Seems trouble free when doing that.

It manually shifts through all gears fine. I confirmed the low power occurs in all scenarios.

I cleared all the codes last night. I drove it again today. No codes yet.
Also, I was looking at some specific trans data. Although it’s not a VCDS/Vag-com, my scanner does offer a lot of data. I was able to see that the G38 (VSS) is reporting the proper vehicle speed. It also showed that the G68 sensor was reporting ~2.55v at 60mph. I looked at current gear selector position, and it matched up properly. One curious thing is “driving mode”. It would be the current gear followed by ‘M’ or ‘H’. So 3H or 4M. I don’t know, probably not important.
Seems the only data I couldn’t access was ATF temp... the box was there, but just said not supported. Unfortunate.
I guess next time I drive it I’ll go through all the data on the engine electronics side. Any tips on what to look for?

One of the best reasons to not have an O1M. Garbage transmissions. In 180K miles, the only issue I have ever had with my 5 speed manual is none. DSG's and auto's in a Dub are really a loosing proposition. They work great until they don't, and then you need to pony up a crap ton of money to make them work right again.

I'll report back at 400K miles when my manual might be showing signs of needing maintenance.

Ol'Rattler said:

One of the best reasons to not have an O1M. Garbage transmissions. In 180K miles, the only issue I have ever had with my 5 speed manual is none. DSG's and auto's in a Dub are really a loosing proposition. They work great until they don't, and then you need to pony up a crap ton of money to make them work right again.
I'll report back at 400K miles when my manual might be showing signs of needing maintenance.

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k...

stomachbuzz said:

k...

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Normally it only takes one or two responses to get that. You're doing way better than usual.

Again, new filter and fluid would be my first step. If there's a suspect relay inside maybe change that too. The valve bodies wear and maybe that's worth changing but Idunno if that would fix your symptoms.

CoolAir's threads go into valve body symptoms.

If you just want to check fluid level it is done by getting the transmission up to a specified temp and filling to overflow. While running if I remember correctly.

Yes there is plenty of hatred for the 01m, my jetta has a little over 240k and and is still functioning. Yes they wont last forever but no automatic does from any of the brands. I dont plan on putting any money into my 01m as I have 5 parts cars that have all the manual stuff required to do a conversion. If you plan on running the 01m I would do one or more transmission services to it depending on how the fluid looks, and just drive it til it dies.

In response to it getting better, the 01m always shifts poorly after the logic is reset. Disconnecting the battery for an extended time should do that. It should shift best in about 500-1000 miles in my experience. I have one in my commuter car for NYC, have had it for about 30k and it came out of a car with 240k on it, but it looked too clean to be original. I installed it,did a valve body for good measure (they suck and usually kill the trans), and filled it with maxlife fluid. Still shifts as it should, some clunks and bumps here and there, but overall it’s ok. I have a spare auto for it in my shed out of one I crashed, after that, if the northeast/nyc hasn’t eaten the body completely, it will get a 5 speed conversion.

Also, these rand-o-fail transmissions are very sensitive to fluid level, and the way everyone says to do it, I feel, leaves the tranny about 1/2 qt low. Also, if the 2 front tires vary in pressure, the shifting goes to hell. So the 1st step is to confirm tire pressures, clear all trans codes, and reset the logic. I’d give a look at the fluid level. Search for how to check, there’s a bunch of threads on it. Then go drive for awhile and see how it goes. If it holds together and smooths out I’d change the fluid(I used maxlife), filter and motor on.

stomachbuzz said:

It would be the current gear followed by ‘M’ or ‘H’. So 3H or 4M. I don’t know, probably not important?

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H is tcc open M is lockup I think. May be the reverse but you should be able to figure it out, lockup usually happens in 3rd, unlocks for the shift, and locks up in 4th immediately, the lockup usually feels like an extra shift in 3rd.

KyleMillione said:

H is tcc open M is lockup I think. May be the reverse but you should be able to figure it out, lockup usually happens in 3rd, unlocks for the shift, and locks up in 4th immediately, the lockup usually feels like an extra shift in 3rd.

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Thanks for your posts. Makes sense. Yep, I just ordered a filter kit and gonna go get Maxlife from Advance Auto later today.
I may take a peak at the valve body when I have the pan off, but unlikely I'll do anything more than "ouuuuuu....ahhhhhh".
I'm still hesitant about spending the time and money to replace the G38 sensor. My scan tool shows that it is reporting the proper voltage ~2.5v. And I'm not sure my trans symptoms are due to a bad G38.
The only issues I have with the trans are occasional 'firm' shifts (wouldn't even call it harsh anymore), and that it hangs at 2-2.5k rpm when coasting on the highway. It immediately settles to 850 upon bumping it into N.
It also does that weird TC lockup downshift thing, but I'm still observing that for consistency.
I don't know, maybe this is just an auto trans thing. In my 8 years of driving experience, I've put like 4k miles on auto cars.
I'll report back on the trans after I do fluid/filter.
I've determined that I certainly have separate engine issues to hunt down. I had thought maybe it is in limp mode, but the symptoms don't fit that well.
1) the limp mode never goes away. Some posts talk about you can reset limp mode by turning the car off, and it will go away until something triggers it again.
2) I unplugged my MAF and the car got sliiiiiiiightly better to drive. Like...I can now approach highway speeds within reason, instead of being scared that a hill might come up. Some people report things like "OMG MY CAR HAS SOOOO MUCH MORE POWER!!!" when disconnecting their MAF. Not the case with my car. I'm still a bit confused about the MAF and limp mode. This thread (http://forums.tdiclub.com/showthread.php?t=409251) says "if power is same or improved, replace the MAF". So what would happen if my MAF is good? The car would run even worse...?
My car isn't being very helpful with trouble codes. I've been plugging in my scanner religiously looking for OBD DTCs and transmission DTCs. Nothing from the transmission, and the data looks good. It registers what gear I'm in, proper G22 VSS data, proper G68 data, G38 looks okay.
No DTCs from the engine electronics. Until I unplugged the MAF. Then it did immediately trigger P1144 "MAF sensor short to ground" and P1556 "Charge pressure control below limit" but no CEL triggered on dash.
With these cars being a bit older, are the OBD systems kinda... "dumb"?
I owned a 2000 Toyota Tacoma for a long time, and while it didn't offer much data streaming on the scanner, it was pretty good about reporting issues via the CEL. The codes were usually vague, and could point to any one of 5 different causes, but I can't believe this VW hasn't thrown multiple CELs for how bad it's running.

Is it worth $30 to rule out the G38 as the reason for problems?
The fluid/filter change can't hurt and the sensor is less than $24 at IDparts.
Order by Monday and save 5%. The trans can cause limp mode so start there.
As mentioned before the proper method is to use VCDS to monitor trans oil temp.
You can get it close by measuring the volume that drains out and replacing that.

flee said:

Is it worth $30 to rule out the G38 as the reason for problems?
The fluid/filter change can't hurt and the sensor is less than $24 at IDparts.
Order by Monday and save 5%. The trans can cause limp mode so start there.
As mentioned before the proper method is to use VCDS to monitor trans oil temp.
You can get it close by measuring the volume that drains out and replacing that.

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5% didn't apply to G38.
But I ordered it. $28 on a "what if". Gotta love it.
Might as well replaced G28 (crank position sensor) because 'ya never know' while I'm in there...

Sorry to be bitter, I just absolutely hate throwing parts at the wall and seeing what sticks.
BTW, I've looked through about 8 credible Limp Mode (referring to engine limp mode - overboosting) threads on here and VWVortex, not a single one mentioned anything relating to the transmission.
Basically goes like this:
1) Unplug MAF
2) Vacuum lines
3) N75
4) Turbo or actuator

If you're referring to trans limp mode, then I would say that my transmission is not in limp mode anymore.

The hang up on coasting is normal. It is supposed to stay locked up even while coasting. Essentially the motor drives the trans to get up to speed and the trans drives the motor while coasting in 3/4 gear.

stomachbuzz said:

5% didn't apply to G38.
But I ordered it. $28 on a "what if". Gotta love it.
Might as well replaced G28 (crank position sensor) because 'ya never know' while I'm in there...
Sorry to be bitter, I just absolutely hate throwing parts at the wall and seeing what sticks.
BTW, I've looked through about 8 credible Limp Mode (referring to engine limp mode - overboosting) threads on here and VWVortex, not a single one mentioned anything relating to the transmission.
Basically goes like this:
1) Unplug MAF
2) Vacuum lines
3) N75
4) Turbo or actuator
If you're referring to trans limp mode, then I would say that my transmission is not in limp mode anymore.

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My 01M got so weird after a failed repair that I think it triggered limp mode.
At least that's what it felt like.
You're going to be guessing a lot of the time until you locate a genuine VCDS.
The other code readers just don't provide the same diagnostic information.

flee said:

You're going to be guessing a lot of the time until you locate a genuine VCDS.
The other code readers just don't provide the same diagnostic information.

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He’s right, We have a modis and a Maxisys scanner at the shop and neither provide as much data as vcds. I use vcds lite. Registered copy is $100. It does most the basic stuff including tdi timing. If not check classifieds for a used cable, the old one is good because it’s an alh.

stomachbuzz said:

Sorry to be bitter, I just absolutely hate throwing parts at the wall and seeing what sticks.

If you're referring to trans limp mode, then I would say that my transmission is not in limp mode anymore.

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I agree, the throwing guess-a-part(s) in gets expensive very quickly.
Bin there, done that.

Generic code readers or scanners have been known to miss codes and/or provide the wrong code.

If your going to keep the car and you have a laptop VCDS is well worth the investment. I have the lite version registered.

Last, keep in mind there is a torque converter in your trans that holds maybe twice the fluid that normally drains out from the pan.

I've read people changed the fluid a couple times to get most out.

Thanks for the replies guys. I've been putting a bit of mental effort into this issue every night when I come back from work.

So far - I've ordered the trans filter (arrived), ordered the Gxx sensor (in transit), and bought some ATF. So will do that soon.
I also ordered a VCDS system. Shipping is taking much longer than anticipated. Oh well.

I decided to set aside some time to rule out other issues with possible limp mode. I unplugged my MAF, car drove marginally better. Almost unnoticeable. So I decided to cheap out and buy some MAF cleaner. Sprayed that. I decided to check vacuum lines while I had the hood open.

What's a good way to check for vac leaks? With a gasser, I would use a propane camping torch and slowly wave it around the engine bay to see when it would rise in idle. Not sure if that's okay on a diesel.

Anyway, I thought it would be a better idea to pull a vac line and put it on a mityvac. I went to pull the line off of the vacuum reservoir (that bulbous thing by the dipstick). I pulled the vacuum line off (very easy! no sticking!) and it let out a gorgeous hiss.

QUESTION: just because my vac reservoir is holding adequate vacuum, does that mean my entire vac system is good?

stomachbuzz said:

........................... also ordered a VCDS system. Shipping is taking much longer than anticipated. Oh well..............

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Guessing you didn't get it from Ross Tech or they're on vacation.

stomachbuzz said:

.................
QUESTION: just because my vac reservoir is holding adequate vacuum, does that mean my entire vac system is good?

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It's a good start, but no, it just means vac reservoir is holding adequate vacuum. The system is made up of many tubes and a few devices.

Went to go look more throughly at my vac line set up, learn a bit, find this notorious "N75" dude, and diagnose some more.
So, I'm using this picture as a resource. I found this on the "how to - limp mode, low power diagnosis" threads. I find this picture often, so I had some trust in it.


So I followed that picture and tried to trace everything out.
I got a bit confused because...it looks like I have 2 N75 valves...



They look identical in shape and size. They both have 2 vacuum lines coming in at the top left, and one going out at the bottom right. They both have an electrical connector plugged in, and they both say "Vac out" at the top.
They also both have lettering on the front, but I couldn't confirm if it's the same part # and all that.




sorry, camera couldn't focus that close :/

I also have another T-connector in my vacuum system (to accommodate 2nd N75) which is not marked on the diagram above.


What's goin' on here?

Smaller photos or thumbnails please.
You're on the right path. The diagram at the top is for a car withe the EGR is removed. Try this link
The N75 and the N18 are nearly identical, in fact they can be swapped for diagnosis purposes. The N75 is the one that has a line down to the turbocharger.
Often these cars keep their factory clothe covered vacuum tubes past their useful life. I can't tell if yours have been replaced. The cloth can be fine, but the rubber can be deteriorated.
Here is a user contributed search engine you may find useful (use the search field near the center)

In fact, the photos are so large that I can clearly see how deteriorated the rubber
of the vacuum hoses is! Replace!