01m

CoolAirVw

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Location
Kansas City Missouri
TDI
Jetta
01m part 1

I’ve been asked to share some info on auto trans diagnosis. I’ve been collecting pictures and data from a few cars that I’ve worked on and I thought I would share the info in this thread.

Edit 4-3-21 Made a video regarding diagnosis on g68 sensor and since this thread is about speed sensors I though I would post a link here.


EDIT: 11-29-18. Made a 01m diagnosis video and didn't want to start a whole thread about it so I decided to place it here. It related to fluctuating, erratic speedometer, and repair process. This is not a how to repair video. Maybe I'll make one as my car has this problem also. If you want a how to video please post in the comments of the video.

This customer’s first call to us was asking, “How much for a transmission on my Bug.” He thought he needed his trans rebuilt or replaced.



Victim…99 Bug 01M
Mileage: 117,000
Complaint…High gear starts

First step in Diagnosis is scan for codes. Some might say first step is checking fluid. I wouldn’t argue, except that you have to lift the car to check fluid, which is a hassle, and you need a scanner to read temp, so why not check codes first?


Here’s the Codes we got…..
00281 vehicle speed sensor (g68) no signal
00297 vehicle speed sensor (g38) no signal

Volkswagens terms are confusing, so I’ll clarify. I don’t like the way VW calls 3 sensors on the trans “Vehicle Speed Sensor”. At least they name them, g68, g38 or g22.

G38 senses the speed of the sun gear shell inside the trans. It’s in the “middle” of the trans right next to the cooler. For a simple understanding of how it is used, just remember that the sun gear shell is stopped for 2nd and 4th and the speed with which it stops and starts, as the shifts, helps the computer determine apply rate of the clutches. In other words it uses this sensor to help control shift feel.

G68 senses the speed of the output of the trans. This is the one under the trans mount with a long harness on it. Obviously, with a transmission that is computer controlled, the computer needs to know what speed the car is going to make up shifting and down shifting decisions. It also compares this sensors signal with engine rpm to determine if the trans is making the correct gear ratio, or if the TCC is slipping.

G22 is on top of the differential section of the transmission and is used for instrument cluster signal, which is what I would normally call a vehicle speed sensor. This sensor doesn't input to the transmission computer and has no bearing on how the transmission works.




Back to the diagnosis…

A quick ohm check of the harness showed that the g38 and g68 sensors were “open”. Ohm checks are good for diagnosing hard problems but if the sensors were “going open” or “shorting” intermittently, then a ohm check is inconclusive.

So we order up a pair of sensors. Wait 3 days. Then we pull the g68 and see this….




No wonder the sensor was open! G38 looked the same, and this is what we saw in its hole. Broken off copper windings..




Both g68 and the g38 looked like this.




“Oh, no!”, I thought! The only logical conclusion is that the shafts are spinning “out of round” and beating the crap out of the sensors! About this time I start thinking, “Lets put in a 5 speed!” (just kidding!)

Well I already had the new sensors…





So, I stuck the g68 in the hole and rolled the car, then pulled the sensor back out, to see if it would “scrape up” the new sensor. It didn’t, so I bolted it up and rolled the car, pulled the sensor out again, and it still didn’t scrape up the sensor. Then I tried driving it. Then I put in the g38.

After clearing the codes and the trans working good, I re-inspected again and the sensors showed no sign of contacting the internal parts.


Edit: 5-15-17
I'm putting this info here because this thread relates to speed sensors. Quite frequently folks might hypothesize that the trans computer might be causing their issue if they replace a 01 speed sensor and the problem is still present. If you put a new g68 sensor in, and the problem isn't solved, then read the following thread where I walked a sharp guy through diagnosis this type of problem. .

http://forums.tdiclub.com/showthread.php?t=477187

To summarize, there should be about 2.5 volts on the sensor wires. This is a "reference voltage" that the computer puts on the sensor wires and the sensor signal "rides" on that voltage. If this voltage is missing then you could have a failed TCM. You can see this voltage in vagcom in the measuring blocks labeled g68 voltage. It should say about 2.5v. Please don't contact me and ask if 2.4v is close enough. If it doesn't show 2.5v and the sensor has been replaced then break out the voltmeter and see if there are 2.5 v on the wires at the sensor and if there isn't then pull the TCM and backprobe the sensor wires and see if there is 2.5v there. If there is not then most likely you need a TCM. I have a selection of TCMs if you need them.

Note: if the sensor fails it will not show 2.5V on vagcom. The above paragraph only calls for a new TCM if there is not 2.5V and the sensor has been replaced.


But this isn’t the end of the story…

Of course we knew we didn’t get all the material out of the trans. So we pulled the pan to inspect.






If someone saw this without knowing the sensors were destroyed, which they wouldn’t if they didn’t scan it, then they would think, “that’s a lot of metal, that trans is failing, we better stick in a 5 speed.”

This design of filter is good at trapping contaminants, so we broke it open!





Once again, if you didn’t know the sensors were shredded, then you would think this trans had some major failure!

continued in next post...
 
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CoolAirVw

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Kansas City Missouri
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Jetta
More info…

Knowing that all filters pass contaminates, I decided to take the valve body apart and clean it. I found a few pockets of metal, and I’m very glad I did clean it.

Edit: the spring seat in this picture moved. It doesn't belong where it is pictured. It belongs one position to the right.




Found some wear on the TCC boost valve. I made a “animation” gif of it as I rolled it on the bench.




This is a high wear item that can cause tcc surging in and out, or slip, and its easily changed. Unfortunately there are other valves that can wear, causing the same thing. Our customer elected to leave this valve in, because he said, “It wasn’t surging before the sensors failed”. He gambled and won in this circumstance, because the trans worked good.

Conclusion… sometimes, you think the trans is junk, as most people would have in many steps in this diagnosis/repair, but you shouldn’t condemn the trans without a conclusive diagnosis.



Heres 01M part 2 http://forums.tdiclub.com/showthread.php?t=250194&highlight=01m

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Joined
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Great Write-Up!

CoolAir,

I have to commend you on your diag of this vehicle. I have seen wheel speed sensors like this but never a VSS. I've personally never taken one of these trannies apart, but it seems fairly simple compared to other things out there, thanks for the detailed pictures. Keep us updated on your 01M findings! You have my vote for TDI 01M GURU!
 

oilhammer

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Location
outside St Louis (where it's safe)
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There are just too many to list....
Good write up Richard. :)

I have no pics (but will try and get some). A common problem I see is DTCs in the TCM for 1 or several (sometimes ALL) the shift solenoids. These are fed through the round 12 pin connector atop the transmission, along with the circuit for the ATF temp sensor. This connector is very easy to get water into, and the teeny little pins on the transmission side can corrode away to almost nothing.

As a general rule, whenever I service an 01M car, I remove that connector, spray some contact cleaner, blow it out, then spray some WD40 back in and reseat the connector. Only takes a minute but can prevent a lot of problems down the road.

That harness on the trans side is not available from VW, I would be curious if the aftermarket has one available.
 

CoolAirVw

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Kansas City Missouri
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Jetta
Solenoid diagnosis is 01m part 2 (or maybe part 3) (ended up being part 5 http://forums.tdiclub.com/showthread.php?t=334614 )

oilhammer said:
That harness on the trans side is not available from VW, I would be curious if the aftermarket has one available.
The aftermarket doesn't have it that I know of. But they should be readily available since guys are swapping in 5 speeds right and left. I just did one and I saved it!!!

Hear that 5 speed swap guys? Save that harness! Post them up for sale in the classified.
 
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steelmb

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MB
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2003 Jetta Wagon
I own a manual trans but if I had an auto I would sure be glad to see this thread and know that somebody has taken the bull by the horns and shared some trouble shooting knowledge on these things rather than just being told to do a VW reman or a 5 speed swap.
 

bayshorecs

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CoolAirVw said:


If someone saw this without knowing the sensors were destroyed, which they wouldn’t if they didn’t scan it, then they would think, “that’s a lot of metal, that trans is failing, we better stick in a 5 speed.”

Nice writeup!

But, wouldn't the only copper in the tranny be from a sensor? If I saw iron or something, I would more quickly come to the tranny eating itself conclusion.

Either way, that much copper floating around in the gear box and TC CAN'T be nice to the tranny in the long run...

At least the guy is able to drive his car for another X miles for cheap before it does fail on him IMO!
 

CoolAirVw

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Jetta
bayshorecs said:
But, wouldn't the only copper in the tranny be from a sensor? If I saw iron or something, I would more quickly come to the tranny eating itself conclusion.
Lots of transmissions have brass thrust washers. So the quick, but wrong thought would be, "Lots of metal, the thrust washers are failing. Needs a $5610.20 trans".
 
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sdeck

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2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
CoolAir,

Excellent write up.

I have gotten a P0725 (sorry, OBDII scanner, not VCDS) a couple times in the past year or so. OBDII scanner indicates "engine speed sensor circuit". Is this the same as one of the codes listed above?

I am at 150K w/ a fluid exchange done at 100K w/ BG synthetic ATF. I am getting ready to drop the pan and change the filter. I will look for copper filings.

Thanks again
 

oilhammer

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outside St Louis (where it's safe)
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There are just too many to list....
You need to get that scanned with a proper tool. Alldata does not even show a P0725 for that car. But I go by the VAG codes anyways. I bet there is something else happening and the generic scanner is not giving the whole story.
 

joetdi

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Midwest
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2-2002 Jettas W/Auto
Note that there is also a bulletin for the G68 on some models. That requires a harness overlay.
 

TDIcrusin

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Jul 24, 2008
Location
St. Cloud
TDI
2001 Jetta GLS
G68 Sensor Fault

Thanks for taking the time to read my question.

Earlier this week, my transmission was acting up more than usual. I think that it even entered limp mode. I check my codes and I got a 00281; the G68 VSS.

I bought the part, and then realized it was not easy to change (Have to drop the tranny!?!) However, I checked resistance at the extention harness, terminals 1+2=825 ohms. 1+3 & 2+3 infinate ohms. No short to ground. I also get the same readings at the harness at the TCM.

Is there a chance that my TCM is bad? Is there any other test to run to make sure?

Thanks
 

TDICADDGUY

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2000 New Beetle GLS
Are you in St Cloud, MN or St Cloud, FL?

You don't have to drop the transmission, you just have to support it from below and remove the mounts. You'll have to order new bolts, as any bolt you disturb there is a stretch bolt that will need replacing.

But before you go doing that, check/clean all connections between the sensor and the TCM. The ones down on the tranmission should be cleaned with contact cleaner (DeOxit is good) and then given a spray of WD-40 to help keep them dry. I've never heard of a TCM failure on these, it just isnt very common.
 

seaglf

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Location
Houston Texas
TDI
2002 Golf GLS Automatic
I bought a 2002 Golf TDI with the 01M a few years ago, and was getting about 46 mpg's on the Highway at 75.

A couple years ago I ran over a Curb which busted the oil pan, and some of the Passenger side suspension components.

I started noticing that I was getting poor mileage and loss of power and slipping on tranny. so brought it to A trusted specialist from this site. Got new Timing belt, clean Intake,and EGR. Also had the Tranny fluid and filter changed.

After that the tranny was slipping worse from 1-2 and then locking up hard, but worked fine after. Added a little more fluid and it seemed better for awhile but still low power and bad mileage.

Got scan Gauge and code p0118. OK since then I have changed Temp sensor, G68 Tranny sensor Crank shaft speed sensor, Maf sensor, New Valve Body, . Didnt find any metal on Magnet in tranny.
cooler adapter. Toped off fluid at 98%....Drove afterwards and was slipping worse, So added a little more fluid thinking that the External cooler and hoses held more.

Shifts better but still slips a little and jerks when at stops.

I am still getting a code for the MAF and when I unplug it there is no change in power.

I have taken it many times to mechanic and had Vag com Tests done. also Reflashed and set tranny to basic settings, I think he did that anyway.

Now when I read the temp on my scan gauge water temp it when it warms up it will read 240,but the flashes 186 for a split second, which was the actual temp...verified by Meat Thermometer in expansion tank.

OK wondering if all this is a indication of a Bad ECM,and/or TCM

My intention is to try to make this tranny last long enough so that I can sell the car with in a year or so, and I'm hoping that the tranny will be good enough that I can get something out of it.

Anyway I'm waiting to see if they sell the new Subaru Boxer diesel here, And if not I wont to get a 200-2003 wagon,maybe with a blown 01m and do a 6 speed manual swap.
 
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seaglf

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2002 Golf GLS Automatic
swap

Since the 01M is made by JATCO is there a better tranny made by them which could be adapted to fit the TDI.
And is possible to swap the new 6 speed Auto made by Aisin onto the ALH.

I actually would rather have a Auto if there was one that was more dependable and had a more gear ranges.
 

oilhammer

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outside St Louis (where it's safe)
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There are just too many to list....
seaglf said:
Since the 01M is made by JATCO is there a better tranny made by them which could be adapted to fit the TDI.
And is possible to swap the new 6 speed Auto made by Aisin onto the ALH.

I actually would rather have a Auto if there was one that was more dependable and had a more gear ranges.
The 01M is NOT made by Jatco. The 09A is. The 01M is in-house Volkswagen.
 

oilhammer

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outside St Louis (where it's safe)
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There are just too many to list....
d2305 said:
I don't understand why anyone with two arms and legs would by a vw slush box.
Because that way they get to USE those legs when the trans gives up, of course! :D

Seriously though, some of us did not have a choice. All B5 Passats sold here with a diesel engine got a slushbox. :rolleyes:
 

seaglf

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2002 Golf GLS Automatic
OK sorry your right I talked to the Tranny guy at the VW dealership, and he confirmed that the 01M for the TDI's where made by VW, some of the 01m's where made By Jatco for some of the Gas models.

I would personally rather have an Automatic, but I wont a tranny that will last awhile ,and give me as good of mileage as the Manual.

Does anyone know if there are any gear splitters,such as the Klune V made for longitudinally mounted engines, but for transverse engines..maybe a European company.

Also has anyone done a DSG swap in a MK4..or what about adding another overdrive gear in the DSG,or 01M.
 

oilhammer

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outside St Louis (where it's safe)
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There are just too many to list....
No, NO 01M transmission was EVER made by Jatco. Please, understand that... PLEASE.

All the 01Ms are the same, just the gearing is different depending on engine mating. The 01P is the Transporter version of the 01M, also made by Volkswagen.

The ONLY Jatco autobox in ANY Volkswagen sold in North America is the 09A 5-speed autobox which was only used behind the BEW diesel and some 1.8t engines, THAT IS IT.

003, 010, 090, 087 are all Volkswagen's own as well. The 01V and 01L are ZF, the 09G and all the T'reg/Q7/Cayenne transmissions are Aisin.
 

TDIJetta99

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03... Faster than yours =]
I'll try to give my tranny guy a call tomorrow and see if he can get 01M harnesses.. He's rebuilt quite a few 01M's for me and so far so good. Even the one bolted to the supercharged VR6 is still together 2 years later.. One of them needed a harness but I'm not sure if he put a used or new one in.
 

seaglf

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2002 Golf GLS Automatic
oilhammer said:
No, NO 01M transmission was EVER made by Jatco. Please, understand that... PLEASE.

All the 01Ms are the same, just the gearing is different depending on engine mating. The 01P is the Transporter version of the 01M, also made by Volkswagen.

The ONLY Jatco autobox in ANY Volkswagen sold in North America is the 09A 5-speed autobox which was only used behind the BEW diesel and some 1.8t engines, THAT IS IT.

003, 010, 090, 087 are all Volkswagen's own as well. The 01V and 01L are ZF, the 09G and all the T'reg/Q7/Cayenne transmissions are Aisin.
Roger that! Dude...I must have misunderstood the VW tranny guy, except that, at least mine was made by VW.


Does anyone have any info on alternative swaps for the ALH's for an Auto..Or anyways to add another higher gear, or a 5 speed DSG swap. From what I have been reading and hearing the ALH is the best TDI made and I know most people put a manual in, But I was wondering if there is an option for an Automatic swap.
 
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seaglf

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CoolAirVw said:
All this conversation is off topic. Please continue your discussion elsewhere.
What exactly is the Topic...Because I am having trouble with my 01M, and I have replaced the G68 suggested by my Mechanic who said he got a code from the VAG COM. I also changed the fluid in the Differential and didn't see any visible problems with the G22... But I am wondering if I am having problems with My TCM or maybe a sensor...I did read you original post that started this thread and It was what helped me to Identify the Part I needed to order originally,as my mechanic just told me where it was and how to change it.
I wished I had a Vag Com but now have exhausted my finances trying to solve my problems with this car.
 
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