Transmission LIMP mode P0706

[DHC]

2005 Passat TDI, 170,000 km. My transmission is now in limp mode. When I read the code it is P0706. I know it is transmission range sensor circuit - range/performance. I searched here and found a few ideas but most of the threads were inconclusive.
I pulled up the carpet on passenger side and found it wet but not flooded. Opened the TCM black box and it was not wet inside. Dried carpet and wires but still the same problem. Even was able to try another TCM from a parts car and still get the same thing. Display is in reverse mode after it clunks into limp, but when first start the car P R and N display okay but not D or any numbers except 2 . If I start out in D it won't shift up until I pull it back to 4 and then it shifts to limp mode.

I am thinking it is the switch on the side of the transmission but would like to know for sure befor changinh as it is a big job and the switch is quite expensive.

 

[DHC]

Anyone know how to test the range sensor to confirm it is bad?

 

[CoolAirVw]

YOu can watch the data on vag-com to see if it reads what its supposed to.

 

[DHC]

Okay....I found the problem. I ended up changing the range switch and it still did not work. So I figured it had to be a wiring problem. Pulled up the carpet on passenger side again and started to inspect wires. There are three wires running to the transmission control unit (TCU) that have a factory splice with two wires on one end and one on the other. I gave them a pull to test the splice and they came right apart. Upon cutting them open I found the wire was corroded green and I had to strip them back an inch to get good wire. After re-splicing everything worked perfect.

Hope this helps someone else. The wires run right along the inner rocker panel on the way to the TCU.

Regards
DHC

 

[pstrahin]

Hi DHC, Just a quick question about your tranny problem. Where were the splices located in the wire bundle, and would you know what the wire colors were? I am having an intermittent similar problem. My tranny will go into limp mode the first thing in the morning when shifting into reverse ( on my slanting driveway) and the fluid is cool. I then back out onto the street and turn the engine off and restart. This clears limp mode and tranny shifts into drive normally and drives good the rest of the day. The cable to my computer runs along the door sill to the front of the car, but has no visible factory multiple splices. Thanks for any help! Regards!

 

[thundershorts]

is the splice you are referring to inside the harness wrapping and brown(brun) in color?

 

[DHC]

Splices are located about middle of passenger door opening. Unwrap the wire bundle running along the sill and inspect each wire. The splices are wrapped with black cloth tape (looks like hockey tape not electrical tape). Can't remember what color they are. when you find them give them a pull to test the splice. Mine looked okay but when I pulled on them they came right apart.

 

[bernbeau]

Thank You, Thank You, Thank You!!!

Thanks DHC.......I had the same symptoms........and performed the described re-splicing of the three wires in question, and voilà, the transmission is back!!!
I can't begin or end thanking you!!! Saved hundreds, if not thousands of dollars!!!!

 

[BobZ]

I would also add that while that junction is the easiest to find and assist with determining some corrosion, corrosion will generally be worse where it connects to the source. Meaning, it will likely be worse at the TCM.
This is only viewed by removing the cover to see it = If you check out these photos, you will see what I mean = https://plus.google.com/u/0/photos/...ms/5704974042636633617?authkey=CJ6V-pyl3I37KA

 

[peiphil]

Sorrry Bob your wrong
A tcm is not a source for B+

 

[BobZ]

Sorrry Bob your wrong
A tcm is not a source for B+

Not sure what you are referring to? If you (not you peiphil, just general readers) would like to know about resistance & Ohm's law, a brief but helpful link here = http://www.allaboutcircuits.com/vol_1/chpt_2/1.html. If you would like to measure the expected resistance within the TCM, this is a good link http://forums.tdiclub.com/showthread.php?t=300712&highlight=tcm+diagram&page=2.

 

[sgraber]

I am having similar problems on 04 jetta after reverse polarity jump start, which wires should I start with

 

[CoolAirVw]

after reverse polarity jump start??? That fries computer sometimes.. I would rule out everything you can 1st though.

Are you getting 706 code? Have you checked with vag com to see if the range sensor is showing PRND321?

 

[Mike-TDI]

What happened with your cold tranny limping reverse problem? I am having this issue now, on a 2005. Trans shop who rebuilt the auto trans can't figure it out.

Also, I cannot locate the splice in this article. It looks like Brown wires. I found splices in purple – red, purple-blue, green-red, but no Brown.

BTW, my transmission failed when the drum for third gear blew apart. I do not remember having these problems before the transmission was rebuilt, so naturally I thought it had to do something with the internals or valve packs or something. The trans shop owner doesn't think so. At least, he cannot find it

Edit: the other reason that I do not think this is a wiring problem, is because it is 100% reproducible by putting any kind of back pressure or large pressure on the transmission in Reverse when it's cold. If it is drifting backwards or moving normally in sync with the throttle, all you have to do is step on the break, do an acceleration that is abrupt, do a tiny break-torque, etc.

I used to think that this behavior of the trans was made worse by being on an angle, because I most commonly experienced it when starting a cold car parked on an, angle left side down in a parking structure. It turns out it's not the case. Even on the flat the same thing happens.

I also have trouble in Tiptronic 1st gear. If I let it get to the top of it's range, use the throttle "unskillfully" or let it bog down, the thing starts to chug and act like it is sort of paniced--it lurches, stops, engages, disengages...It is like when a person drives a manual, but doesn't release the clutch when coasting down.

In general, I don't think the transmission "let's go" when I decelerate to stop. It also seems really uncertain or a little slippery in going between 2 and 3 or 3 and 4...like it is hunting, or maybe like when someone is too slow to let the clutch go and starts to accelerate with it partially engaged, and then waivers with the foot--a little on/a little off/a little on, then off.


any help would be appreciated ,
Mike-TDI

Hi DHC, Just a quick question about your tranny problem. Where were the splices located in the wire bundle, and would you know what the wire colors were? I am having an intermittent similar problem. My tranny will go into limp mode the first thing in the morning when shifting into reverse ( on my slanting driveway) and the fluid is cool. I then back out onto the street and turn the engine off and restart. This clears limp mode and tranny shifts into drive normally and drives good the rest of the day. The cable to my computer runs along the door sill to the front of the car, but has no visible factory multiple splices. Thanks for any help! Regards!