Volkswagen Passat Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
357 Posts
Discussion Starter #1 (Edited)
I have a 2003 Passat Wagon AWM and when I turned it on today all the PRDN etc lit up on the dashboard. In other words it wasn't just P since it was in P. I was able to change gears (although there was lots of popping from/to reverse) and drive, and when I shut the car off and turned it back on everything was back to normal. I've read this is a common issue and like many others I received this code:
P0706: Transmission Range Sensor Circuit Range/Performance

I also received this fault code, listed as possibly pending or manufacturer specific:
C02C2: Unknown code - More information may be available on the web

I am using the Torque app with an ELM bluetooth OBD device to get the codes. I do not have VAGCOM. Google didn't give much on the code and this forum doesn't have anything on it. I found an audi site that has it listed and says it's a transmission related code but nothing else.

For now I've cleared the codes however does anyone know what it is, or have you seen it, or if you are a VW tech would you mind running the two codes together and post what comes back so I can get a better handle on fixing this. Thanks


SOLVED: Thanks to the forum members here. The culprit was both corroded wiring and a bad transmission range sensor (aka neutral safety switch, aka multifunction switch). If you don't want to read all the posts see post #17 for the solve. I never found out what the C02C2 code was.
 

·
Registered
Joined
·
5,282 Posts
The range switch, outside your transmission on the driver's side, might be bad, or it could be an electrical connector issue. The range swich contains a group of fairly ordinary looking micro-switches, arranged around a round cam. If any of these switches were to not work, the range code would result. I'd start by getting the driver's side front on a jack-stand, removing the left front wheel, then uncoupling the range switch connector to spray both pins and sockets with a contact cleaner. While at it, disconnect the other connector near it, which is the wiring for the transmission's solenoids and sensors, and clean/lube those contacts too.
 

·
Registered
Joined
·
242 Posts
The range switch, outside your transmission on the driver's side, might be bad, or it could be an electrical connector issue. The range swich contains a group of fairly ordinary looking micro-switches, arranged around a round cam. If any of these switches were to not work, the range code would result. I'd start by getting the driver's side front on a jack-stand, removing the left front wheel, then uncoupling the range switch connector to spray both pins and sockets with a contact cleaner. While at it, disconnect the other connector near it, which is the wiring for the transmission's solenoids and sensors, and clean/lube those contacts too.
X2. Had this same issue on a 99 AEB and ended up replacing the range switch with one from the junkyard and it solved the problem. Cleaning the connectors is a good first step and may fix the problem without replacement.
 

·
Registered
Joined
·
1,339 Posts
The tranny lights all light up because of the range sensor, indeed. C codes are body related but I don't know what it translates to in VCDS language. All the windows/sunroof/door locks work fine? If not, that could be your C code.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #6
Thanks guys. I looked into this some more today and I have a leak somewhere above the transmission that may be related so I'm looking into that. The PRND432 comes and goes, today it was on and I couldn't get the car up the sloped driveway. Another time I was able to shift gears and I went through each gear slowly and I noticed when I went to 4 the display would blink 4 if I put a little pressure on the shifter in either direction. The other gears didn't do that.

Anyway I'm not sure what that means but it had me wondering if there could be something in the shifter that could go bad. I know some later model VWs have some sort of sliding plastic plate in the shifter that can crack. Does a 2003 Passat 1.8T automatic triptronic have that plate as well? If it's worth looking into is there a good DIY to take apart the shifter for B5.5s? Can I just pop the plastic pieces off? I don't see a screw to disconnect the handle from the lever...

Thanks
 

·
Registered
Joined
·
5,282 Posts
The knob is not screwed on, but there is a procedure for removing/installing it, involving pulling the thumb button out enough to allow the handle to rotate, then pull up and off. I don't remember exactly, so wait for someone who knows for sure, or perhaps get the Chilton maintenance manual, which has a pictorial on how to do all of this, including the trim around the shifter. But don't just try to pry that up either, removal is more involved than that.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #8
The knob is not screwed on, but there is a procedure for removing/installing it, involving pulling the thumb button out enough to allow the handle to rotate, then pull up and off. I don't remember exactly, so wait for someone who knows for sure, or perhaps get the Chilton maintenance manual, which has a pictorial on how to do all of this, including the trim around the shifter. But don't just try to pry that up either, removal is more involved than that.
Thanks. I bought a Haynes repair manual (Audi A4 96-01/Passat 01-05) manual on eBay. It's coming next week.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #9 (Edited)
The leak I talked about earlier was a coolant leak which I've solved thanks to the forum and appears to be unrelated. I examined the range switch connector pins and they look to be in excellent condition (although I have no idea about the internals of the range switch itself).

I had a vagcom scan done:
17090 - Transmission Range Sensor (F125)
P0706 - 003 - Implausible Signal
Freeze Frame:
RPM: 928 /min
RPM: 896 /min
RPM: 0 /min
(no units): 0.0
Torque: 28.0 Nm
Temperature: 27.0°C
T.B. Angle: 0.0°
(no units): 1.0


Also, I received my Haynes manual. I removed the shifter but did not see a sliding plastic plate inside of the panel so I can rule that out. I did a writeup for how to remove the shifter:
HOWTO: B5.5 automatic/triptronic shifter removal

I pulled the transmission control unit under the passenger carpet and wow that whole area was soaking wet.


I have no idea what caused all the water. I really need to dry it out, the foam underlayment is sopping. I can't pull the carpet back all the way though. There is an area to the left of the passenger footrest that looks like it's in there permanently and there's no way to pull the carpet from it. It's below the black plastic thing in this next picture. What do you guys think, should I cut it with a razor up there to pull the whole thing back? Is there a way to disconnect it?
 

·
Registered
Joined
·
59 Posts
This is a common problem. Lift the carpet and throw dry towels under - apply pressure. After you get the most of the water out, throw a fan under it.

There can be many causes of the leak but I think blocked sunroof/cowel drains are often to blame

Check the TCM harness for broken wires and check it to see if it got wet inside.

I happen to have a good TCM that I might be selling, as well as a long chunk of the harness.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #11 (Edited)
This is a common problem. Lift the carpet and throw dry towels under - apply pressure. After you get the most of the water out, throw a fan under it.

There can be many causes of the leak but I think blocked sunroof/cowel drains are often to blame
It was so wet I cut it back and then absorbed what I could of the liquid. It's still soaked. I just couldn't work on the wiring with it in the way. I have a suspect, there is a water drain pipe funnel that is in the area that was wet. I assume that is the funnel for the evaporator to exhaust water to outside?



Check the TCM harness for broken wires and check it to see if it got wet inside.

I happen to have a good TCM that I might be selling, as well as a long chunk of the harness.
The TCM looks clean inside, it looks like the water didn't permeate. Thanks for the offer though. I did check the wiring to the TCM and found three wires that are spliced right near the branch off: purple/red, purple/blue, green/red. The branches go to the TCM. The green is corroded. Here's an overview picture. The splices are about a third of the way back from the front of the passenger door opening.



Here's a closeup pic of the corroded green/red wire:



I don't have wiring information for the TCM. If anyone has wiring info for the 2003 Passat 1.8T AWM can you tell me what the purple/red, purple/blue and green/red wires are? It may be in a Bentley manual but it's not in my Haynes. Also, is anyone aware of any other splices for the wiring? I think I looked pretty closely but that's all I found.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #12 (Edited)
Well it's definitely something to do with the green/red wire. I disconnected the green/red wire from the TCM and went through each gear with a borrowed VCDS. I made an animated GIF that shows what happens in each of the gears with that wire disconnected. The animation is about one minute long and each frame is four seconds. The animation should show below.


If you want to see the individual frames here are links to each frame: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13


I've stripped the green/red wire back and it's still all corroded. Has anyone else had to replace this wire?

I'm still looking for the Transmission Control Systems Diagrams for 2003 Passat 1.8T AWM w/ 01V tiptronic automatic transmission. I have not been able to find them anywhere online (I've even gone to Russian sites) and they are not in my Haynes manual. Anyone have them? I'm interested specifically in the function of the spliced wires, purple/red, purple/blue and green/red. Thanks
 

·
Registered
Joined
·
1,339 Posts
Can you tell me which pins the wires go to? I might be able to look it up.
One common problem with water ingress is the drain in the A pillar. Open the door and look at the rubber nipple between the door hinges. Cut it with a blade as close to the body of the car. This is actually a recall procedure from VW :)
 

·
Registered
Joined
·
357 Posts
Discussion Starter #14
Can you tell me which pins the wires go to? I might be able to look it up.
Thanks. I did an ohms test with a multimeter:

Pin 9 - Green/Red
Pin 46 - Purple/Red
Pin 47 - Purple/Blue

I got rid of all the bad connections and made new ones but now the problem seems to be worse. I used 18 AWG copper wire. I had to remove a lot of the green/red wire, I stripped one section back about 2 feet before I got to copper that wasn't corroded. For each wire once I got to an area that wasn't corroded I used heat shrink butt splices and liquid electrical tape.

PRND432 lights up as soon as I switch into reverse now. I'm sure that all the connections are right and crimped securely (I did a tug test). The 18 AWG copper is thicker than the OEM wires, which is about 22 or 24AWG? Has it ever happened that using a thicker wire actually increased resistance? Seems counterintuitive but I'm grasping at straws here. Does anyone know how much voltage should be flowing into the TCM from any of those wires? Or even what wiring diagram or testing procedure I should look for, I don't even know. All pointers welcome.

One common problem with water ingress is the drain in the A pillar. Open the door and look at the rubber nipple between the door hinges. Cut it with a blade as close to the body of the car. This is actually a recall procedure from VW :)
I don't think I have this, I can't find it. Is it for a sunroof? I don't have a sunroof.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #15 (Edited)
Does anyone know how much voltage should be flowing into the TCM from any of those wires?
I disconnected the TCM and used a multimeter to monitor pins 9, 46 and 47 as I shifted through each of the gears. I set the multimeter negative (-) probe to ground (aligator clipped to a screw secured to the metal frame near the shifter), and the positive (+) probe was connected to the female receptacle for each pin I was testing on the TCM wiring harness. In other words I didn't actually pass through to the TCM, it was entirely disconnected.

Pin 9 (Green/Red) shows 13.5v DC in D, 4 and 3. All other gears nothing.
Pins 46 (Purple/Red) and 47 (Purple/Blue) show no voltage change in any gear. I'm starting to think these pins may be related to the tiptronic system because I found purple/red and purple/blue wires running to tiptronic circuit board on shifter.

I had the car running for the tests but I'm not sure if it was necessary. I'm not sure if those results are appropriate or not.

EDIT: I found the transmission wiring diagram and I can see now that Green/Red goes from the TCM to pin 5 on the multifunction range switch (F125). Now that the wiring has been repaired I'm starting to think I need a new range switch/sensor :(
 

·
Registered
Joined
·
8,940 Posts
According to your VCDS animation, you are losing supply voltage (from terminal 15).

Check the black wire that connects to pin 1 on the multi function switch, pins 54 and 55 on the TCM, the ignition switch, and fuse panel.
Most likely a fault in the splice between the TCM and MFS, there is also a splice between the ign sw and fuse panel.

Check the switches in the MFS, measure between pin 1 (Black); and the individual switches P3 (Green/White), P5 (Green/Red), P2 (Green/Grey), and P4 (Green/Violet).
Test each switch through the range of shifter positions.
 

·
Registered
Joined
·
357 Posts
Discussion Starter #17 (Edited)
According to your VCDS animation, you are losing supply voltage (from terminal 15).
Yes but I think what happens is the TCM cuts off terminal 15 voltage when it goes into limp mode. Still that is good advice to check those things.


Now that the wiring has been repaired I'm starting to think I need a new range switch/sensor :(
I have installed a new range sensor and that appears to have fixed the limp mode problem. Here's more information:

As mentioned repairing the wiring had actually made the problem worse, maybe because the clean voltage made easier for the TCM to detect there was a problem and/or maybe the detection is feedback adjusted. So I searched for diagnostic procedures and found one in the Audi 01V/01L Automatic Transmission Technician Reference Guide. The relevant information can be found on pages 41-43 (in a PDF viewer will show as 45-47 since pages at the beginning don't have a number). Note that the manual refers to the range sensor as a Multifunction switch or MFS. Here's a pic from the manual:



Interestingly the MFS positions appeared to test correctly. However it failed the wiggle test. That is where you put a little pressure each way when you are in a gear. As I noted earlier in the thread I had problems with 4, and now also from P-R and back. The P-R-P caused the limp mode when I did the testing. It took a few tries. I should also note there is no way to test the Z positions from what I could tell (or maybe that is how you test the Z positions?). I did see Z positions occasionally after I changed to a gear, and sometimes they lagged disappearing and showing the actual gear I was in so maybe that's another sign.

After doing the diagnostic it was pretty apparent I needed to order a new range sensor. The range sensor is part 01V919821B. The one I ordered is made by Standard Intermotor part NS-349. It doesn't say it's OEM but it has a 3 year warranty (some others have just 1) and mine has VW and Audi markings on it.

Removing the old range sensor and installing the new one was difficult. There are a few guides floating around but my favorite is a thread from the AudiWorld website. It has great pictures:
Audi B5A4 1.8T Transmission Multifunction Switch Replacement Writeup - AudiWorld Forums
There's also a video on YouTube:


A few important notes:
  • The DIY thread is from 2007 so you'll notice the price for the part is quoted at $360 but these days it shouldn't cost more than $200.
  • The DIY thread says use a 17mm wrench but if I recall correctly I needed 16mm.
  • You will be disconnecting the transmission mount so you will need to support the transmission. I suggest you use a scissor jack with a wood base to get the jack as close as possible. Then turn until just snug. I suggest this because after you disconnect the mount if the jack isn't snug the transmission weight will cause it to sag a little like mine did. For reinstall I had to jack it up just a tiny bit (one to two turns) so all the holes would line up. Be careful not to knock over the jack as you will be working under the car very close to it.
  • There are no torque specifications in the DIY thread or the video. I had trouble finding them myself:
    Request for torque specs related to MFS replacement (Transmission Range Sensor)
  • With my car (2003 Passat 1.8T AWM) it was possible for me to remove all the mount bracket bolts without a socket swivel or 8mm ball head hex. I did it from under the car using 0 1 or 2 extensions and a regular hex head.
  • Last but not least the hardest part for me was reconnecting the MFS connector. I removed the bracket that held the connector to the transmission and even then as hard as I tried I couldn't connect them together. I must have tried continually for half an hour with all my strength. It went almost all the way but not enough to lock in. It has to lock in or that can be really dangerous. I suspect the CRC electrical cleaner I sprayed in the connector (harness side) may have swelled the gasket in it but I don't know. Anyway I ended up using a channel lock to squeeze the connectors together by using a ziptie trick. If you're going to attempt that make absolutely sure the pins are all going in properly and aren't bent out. I confirmed visually that it actually properly locked in place. Here's an illustration of how I did it:




Also I redid my wiring repair. Initially I had used Tyco Shrink Butt Splice Soldergrip but I read on this forum and others that it's not a good idea to use soldered connections; specifically people saying that VW forbids it on the wiring harness. So I redid the connections using heat shrink butt splices that could be crimped. However in the case of the 3 way ones they were more difficult and for each I cannibalized a crimp from inside a large butt splice and used it in combination with a heat shrink and electrical tape.

Before crimp and heatshrink:


After crimp and heatshrink:


As an extra precaution I later covered all joints with liquid electrical tape:


I hung them up in the air with temporary zipties like that so I could do that whole area at once since the liquid tends to stick to everything and they need time to dry.


Unfortunately I'm not entirely done yet. I still have water infiltration! I've spun that issue off into a separate thread:
Water infiltration issues in my passenger footwell
 
1 - 17 of 17 Posts
Top