Auto Trans stuck in 1st

[iampapabear]

Bought a 2000 Beetle (2.0 gasoline, 01M 4-speed auto trans) for my daughter. Beautiful car! Drove it home (1000 miles) with no problems, drove like a dream. Parked in driveway and several days later noticed fluid leak underneath. Thought it was trans fluid at first, turned out to be antifreeze.

Found leak - coolant flange.

Changed coolant flange. Refilled system with G12.

Between starting and completing the work about 6 weeks passed.

When complete, tried to start car for test drive. No go, battery nearly dead.

Interior lights came on weakly, dash lights that normally light during key-on to start just flashed on and off.

Put charger on and battery wouldn't charge. Auto charger kept cycling on and off. After about half hour tried to start, no dice. ALSO, no power to anything anymore.

Replaced battery.

Car started just fine.

Test drive.....car won't shift out of 1st.

Holy cow, what happened? Any suggestions.

[IndyTom]

Sorry to hear about your troubles. Seems everything started to happen all at once.
Change the transmission fluid and see what happens. Those old 4 speed autos are known for valve body failures and the G68 Output speed sensor going out.
Have it hooked up to a VCDS/Vag com scanner and see what the codes are. Usually, those automatic transmissions are very expensive to fix. If it is the Valve body you might as well swap out the entire transmission since it isn't worth fixing just the valve body which the dealer charges you anywhere from 1700 to 2700 dollars for when you can get a brand new transmission on line for right at 2000.

[iampapabear]

Car has only 28,000 original miles on it.

Had no transmission problems prior to replacement of coolant flange.

Trans fluid level checked ok, looks clean, not opaque or burnt.

Is it possible that the speed sensor would keep it locked in 1st, if the speed sensor were to go out?

Is it possible that leaking coolant could short out the sensor?

Where is the sensor located?

[iampapabear]

Update.

Took car (at 15 mph) to local Autozone. Had them use OBD to see what codes were up.

P0121
P1544
p0510

Made mistake on earlier post. Car shifts from 1st to 2nd, but stays in 2nd.

[Smileybug]

Looks like throttle issues of some type:


16505/P0121
Throttle/Pedal Pos.Sensor A Circ Range/Performance

17952/P1544
Throttle Actuation Potentiometer Signal too High

16894/P0510
Closed Throttle Pos.Switch Malfunction

I'm not well versed in this stuff, but I'm sure someone can give you some insight.

[IndyTom]

It is quite possible that the coolant shorted out one of the three speed sensors on the Automatic transmission. If I had to guess it is probably the G68 sensor located under the transmission bracket. It's the one with the pig tail on it.

I found this on another forum. It refers to a Jetta transmission issue but the transmission is basically the same.

I'm posting this because I had no luck at finding information in the forum to assist in solving the problem of our Jetta being in transmission Limp Mode. Limp mode results in the transmission operating only in 1st and 3rd gear, with upshifts at about 4000 rpm.
Our 2001 AEG with 01M automatic transmission went into limp mode and showed OBD code P0722. Bentley describes P0722 as transmission output speed sensor. The weather was bad, my wife was screaming, so I took the car to the dealer. They called and said the car ran fine on a test drive, but still showed a DTC for Vehicle Speed Sensor. I paid them $150 to replace the sensor.

A couple weeks go by and the car is back into Limp Mode. I start researching it. The 01M has three speed sensors on the transmission. These are identified in the wiring diagram as G22, G38, and G68. G38 and G68 connect through the harness to the Transmission Control Module (TCM). G22 connects to the back of the instrument cluster. My professional VW mechanic, with a shop full of manuals, TSB's, and computers, had replaced the speedo sensor. I went back to the dealer and had this conversation:
Me: There are 3 sensors. Two go to the TCM and one goes to the speedometer. The complaint was transmission in limp mode and you replaced the speedometer sensor. I don't think that's right.
Dealer: These things are all interconnected. It could be the speedo sensor causing the transmission problem.
Me: Then why is it doing it again? Doesn't VAG-COM tell you which sensor is bad?
Dealer: We can't tell you anything unless you bring it back in and let us do a diagnosis. That will be $110.
Me (unspoken): When pigs fly, you ******!

VW Technical Bulletin C01-99-02 addresses the issue of speed sensors and DTC's. It shows the location of each sensor and identifies it by the wiring diagram "G" number. It also tells which sensor causes each DTC, but it is listing VW DTC's that are not cross-referenced to OBD codes in Bentley. It also implies that the VAG tool shows the wrong sensor for DTC-00281. Bentley also has illustrations in the AT section to identify the sensors by the G number.

The problem then becomes to determine which of the sensors is associated with the P0722 code. P0722 is "output speed sensor," but nowhere are any of the sensors described with those words. My successful repair would indicate the following:

The G38 sensor, on the center top of the transmission, directly accessible under the battery tray, is apparently the input speed sensor referenced by OBD code P0717. The G22 speedometer sensor is on top of the differential housing, in a silver heat shield behind the engine. The G68 sensor is the output speed sensor referred to by code P0722 and is on top of the transmission, under the mount support bracket.

Bentley makes the replacement of G68 sound terrible. It is not. Remove the air cleaner housing and battery tray. G68 is out of sight, under the transmission mount support bracket. Support the weight of the transmission on a jack, lifting on the skid plate. The support bracket must be removed. VW says to replace all 4 support bolts (these are the same bolts replaced in a timing belt replacement). Instead of replacing them, before removal I used a Sharpie to make match marks on all 4 bolts. When replacing them I realigned the marks, plus 1/12 turn. If the transmission falls out, I'll be sure to post it.

With the 4 bolts out, lower the transmission about 2 inches to make room to move the support bracket aside. You don't need to get it out of the car, just move it aside so you can get to the speed sensor. Everything from here is simple remove and replace.

Buying the sensor was something of an ordeal. The parts guy brought out the G22 speedo sensor (357 919 149B). If I had not had the Bentley manual and VW TSB with me, I think he would not have believed that the other sensors existed. The G68 output speed sensor has a pigtail harness; the G38 input sensor does not. My G68 is 01M 927 321B. My G38 is 095 927 321B. Check your numbers; the parts guy said there was a G68 number change on later models.

It's now been about 3 months, and everything is good, so I believe this info is right.

So before swapping out the transmission it might be cheaper first to replace the G68 Speed sensor.
A little tricky to get to but not impossible.

Oh, here is the link to this post:
http://forums.vwvortex.com/showthrea...e-Speed-Sensor

Here is the Sensor that he is referring to:

Home Page > Search > 01M 927 321B > ES#267784 Transmission Speed Sensor - 01M927321B

If you have a friend or Orger near you with a VAG Com they could scan your car and get more detail than a OBDII Scanner puts out. I hate for you to start replacing parts and still not fix the actual problem.

[Smileybug]

None of the codes are the 722 code. All three of the codes pulled point to the throttle.

In some searching on those codes, looks like its relating to the throttle position sensor, which seems like is actually part of the throttle body. You can start by cleaning it and getting an adaptation done on the throttle body and see if it fixes things.

[iampapabear]

The solution was so simple. Reset the throttle position sensor!
From engine off, key out, trans in park. (1) press gas pedal all the way to the floor (2) insert key and turn to on - do not turn far enough to start engine (3) wait ten seconds (4) turn off key and pull it out. Take foot off of gas pedal. Wait a moment and go for a drive.

All works as supposed to! Car starts and runs smoothly. Shifts like a dream. Goes through the gears like its supposed to (maybe even smoother than before?) HOT DOG! back in business.

[IndyTom]

Glad it was something simple and "FREE"