Electrical Issues with Passat B5. TCM? ECU?

[bobetko]

My Passat (B5, 1.8, 2003, 100K) shut down almost 2 months ago:
- During driving I noticed my dashboard lights and displays were blinking, and some crazy (random) things were showing up on little display (the left one). I came home, turned off car and couldn't start it any more. It would start, but engine would shut down immediately (almost seems like there is no gas). After taking key out, radio would keep working and dashboard kept blinking. I tried taking out and reinserting all the fuses in hope that blinking will stop, but it kept blinking. Finally I disconnected battery and everything got back to normal. Car was working fine. This happened 2 more times. Second time I again disconnected battery and "solved" the problem. But, third time, disconnecting battery didn't help. Can't start car now, and if I keep battery connected it drains out in couple of hours.

I took car to some friend (of my friend), who owns car shop and he specializes in European cars. He told me that ECU is bad and maybe couple of clusters (not sure what clasters are). The worst, he didn't really know if ECU is only problem. He said after he installs new ECU he will see what else has to be replaced. I was ready to do that, but it took him almost month to order new ECU, and I decided to take car and move it to official WV Service. I was adviced by lot of my friends who owns European cars that, even though they are expensive, they know their job and instead of some wannabe mechanic poking around trying to guess what might be wrong. Let "professionals" do the job. At VW service they have resources and they will know exactly what is wrong with the car. Well, that is a big LIE. They are no different then any other wannabe mechanics you might stumble upon. They don't have resources to test all the parts. For example if they believe that some part is bad, they can't try that part to see if part is really bad and if that will solve the problem. Once they put part in the car they can't return it to the part department (company policy)...

Anyway, initially they claimed that in one hour they will tell me what I need to do. During next 10 days they called me several times to apologize for the delay, and they confessed that they have issue with car, and don't know what the problem is. Finally, they came out with statement that TCM is bad, and replacement will cost $1,600. I asked them if that is final. I wanted them to confirm that new TCM will solve the problem. He said no. He was not sure. He will see after I approve installation. I might end up spending more 1000s on other parts as well. And then he explained everything about their policy, and how they can't actually try before I buy.

To summarize:
1) I really don't believe them. Is it possible that it would take 10 days for official VW mechanic to diagnose that TCM is bad. Wouldn't that be first thing to test since a lot of people have issue with that. I paid $270 for diagnosis which basically says that it is probably TCM and who knows what else. They advised me to dump the car.

It is possible that TCM is bad cause I had few times situations where my car (passenger side) was full of water after hard rain. Later I learned that TCM is under passenger's seat. An idiot who designed this car should be given a medal.

The car is now in my garage. I am planning on my own to get out TCM and buy another one on Ebay. I am not big on fixing cars, but I am able to follow directions and I am not afraid of getting dirty. I found some blogs with pictures that explains how to replace TCM. It doesn't seem a big problem. The only thing is, I have to find exactly the same TCM that I have.

Would you advice me to to that? Thanks.

PS. VW mechanic is no better then your next door mechanic. They both have no clue.

And, thanks to anybody who has patience to read this.

[scotts13]

Sounds like you need a new VW dealer. The ones I've been dealing with for the last 30 years or so would not charge me for a bad diagnosis (or at least, not for a re-diagnosis) and if they have to swap parts to figure it out, I only pay for the part that fixes the problem.

BTW, the TCM (Transmission Control Module) should have nothing to do with your problems. Perhaps they said the CCM (Comfort Control Module) under the carpet on the other side?

[bobetko]

They said Transmission Control Module is bad. I have it recorded on my voice mail.

Is there a way to test TCM if it works properly?

If I would prove that it works I would have grounds to complain and maybe demand my money back. The thing is, he said $1,600 for new TCM, and he implied that I may be spending more money later and that's how he got me out through the door. That is exactly what they wanted. They didn't know how to fix car and they wanted to get rid of it.

[crnee]

Alright this will be my first contribution to the Volkswagen/Audi world. Here is the story...

Before I begin, this fix is time consuming, aggravating, and requires the utmost patience. Anyhow, 01 Passat 1.8t AWM, non-corrosive environment. Helped a family member pick it out approx 1.5 years ago. From word go coolant level light flashing, verified false alarm. Told them to purchase new coolant tank installed, still same problem then, the vehicle's fuel pump relay started acting up, along with various systems. That told me to start looking into ECM,CCM,Grounds. As I started diagnosing systems 1 by 1 could tell previous owner or someone had already been where I was going up to the ECM. Pulled CCM unwrapped wiring harness all splices were pristine along with CCM. After viewing electrical diagrams for 1 day discovered that seemingly separate systems were actually related. Here is the "FUN"? part, removed interior from instrument cluster back to rear seats. After doing that started looking at ground points one on each B-Pillar one on each A Pillar one under center console, and one chassis to battery. After pulling ground nuts discovered that instead of using bare nuts they were painted with the body, leaving a 1/8" +- ring of paint buildup around the edge of the contact side. maybe when the car was new this is okay, but after a few years where it was just pushed into the body humidity creeps and leaves an oxidized surface and now has to try and find ground through the nut with the paint buildup it can't. So what I did was take 100 grit sandpaper on a flat surface and sanded the ring of paint off completely. After reassembly, motor ran smoother, turbo more responsive, coolant level light quit flashing, relay quit chattering, and some other things that I can't remember right now. Sorry for the poor construction, not good at telling stories. Anyhow if someone else having similar multisystem malfunctions, and trys this let me know the results on your vehicle please. May have found the problem source for allot of ECM appearing problems.
Next in post is a good resource for the B5, I know its Russian but there are English docs
Volkswagen B5 (PL45): VW Passat B5, Passat B5.5, Audi A4, Passat Lingyu, Passat Lingyu B5, Skoda Superb, ,

[crnee]

Sorry, forgot one ground under coolant tank.

[bobetko]

What is possibility that I have bad instrument cluster or bad CCM? Or some other cluster?
I had some issues previously with display showing some funky stuff especially during bad weather. To my logic, even with these two bad, the car should be running? Right? I am trying to downsize list of possible problems...

The first mechanic said that I have bad ECU because he couldn't read any error codes from ECU (he said he couldn't communicate to it). VW service didn't mention ECU, they said TCM is bad. I am leaning toward bad TCM because I know that, in at least two occasions, TCM was completely submerged in water for few days. Also, tiptronic didn't work last time I tried it. I read somewhere that transmission was maybe in LIMP mode. What does that mean?

I ordered new (used) TCM for $180 and VAG COM cable, so I hope next week I will have better Idea what is going on with car.

Please let me know if you have any ideas. Thanks.

[soundguybob]

Since yo've had water intrusion problems, it wouldn't surprise me at all if you have at minimum a bad TCU. You very likely may also have a bad CCM, or corrodes splices in it's wiring harness, as well as potentially compromised ground points. Personally, I'd pull the front seats and carpet, and have a good look at both modules that are under the carpet, as well as peeling off the bundling tape from the wiring harness and checking all the factory splices. The splices will be in the section between the CCM and up to the kick panel area. Since the modules communicate across a common data bus (one for the engine systems, and one for the comfort systems), one bad module can screw up that data bus and wreak all kinds of havoc.

[PZ]

Depending on how the water intrusion happened, either VW or your car insurance may cover the repairs. I know of 1 owner that VW paid for a new wiring harness in the cabin of the car. It was over $3000 in repairs.

[bobetko]

Thanks guys. I don't think I can prove to VW when and how water intrusion happened. One day (actually 2 times) I got in the car and I noticed 2 or 3 inches of water on passenger side. I really didn't take it very seriously. I cleaned everything, dried as much as I could. Tried to locate were water was coming from, but couldn't figure it out. I thought it was coming through the doors.
I didn't have slightest idea about CCM, ECU and TCM being in the floor. I'll be thinking twice every time I will wan't to run over some puddle of water.

Now: Are there any components that can be ruled out considering the problems I have?

Soundguybob, What is a kick panel?

It seems to me that when one thing is out, the whole thing dies. That is so no smart. The more I learn I get more disappointed.

[dschwarz]

Passenger side = TCM, driver side = CCM (assuming standard US passat)
So it's entirely possible your TCM has drowned, but the symptoms sound more like a drowned CCM and/or harness. This is a sign of water intrusion but it's likely not from puddles. It's from your sunroof drain, battery drain or windshield cowl. You need to:

1) Dry out the footwells completely
2) Get the car under cover before the next rain
3) Find and fix the leak (google for water ingress passat)
4) Repair and/or replace wiring harnesses, CCM, TCM

You can do some of it yourself and leave the rest to an independent VW specialist. I recommend getting a used, known good CCM and TCM to save money. Must get the EXACT RIGHT PART so check the full part number.

[soundguybob]

The kick panel is the plastic panel forward of the front doors, on the sides and under the dash. There are connector stations behind each of them. You'll be surprised at how many wires are present in these cars once you see all the connectors!

[PZ]

Thanks guys. I don't think I can prove to VW when and how water intrusion happened. One day (actually 2 times) I got in the car and I noticed 2 or 3 inches of water on passenger side. I really didn't take it very seriously. I cleaned everything, dried as much as I could. Tried to locate were water was coming from, but couldn't figure it out. I thought it was coming through the doors.
I didn't have slightest idea about CCM, ECU and TCM being in the floor. I'll be thinking twice every time I will wan't to run over some puddle of water.

Now: Are there any components that can be ruled out considering the problems I have?

Soundguybob, What is a kick panel?

It seems to me that when one thing is out, the whole thing dies. That is so no smart. The more I learn I get more disappointed.

Search for some of the water intrusion threads. There are plenty and they will point out the sources of the problem. It is well worth your time to try to get a dealer or your insurance to cover this.

[Troy Jollimore]

Scotts, I've NEVER come across a dealer that 'only' charged for the part that fixed the problem... You've got a Gold-star dealer there, my friend!

bobetko, They'll pay tons of your money to just throw parts at the problem. Your issue is most likely a dying battery, bad battery connections, a bad ground somewhere, or a bad alternator. I would troubleshoot these parts first before moving on to $1500 computers! Also, pull the carpets up in the front of the car and give them a good drying out. Check the two computers there (as mentioned above) for any damage, and REALLY check the wiring to make sure nothing's shorting out against the floor, or just disconnected.

[scotts13]

Scotts, I've NEVER come across a dealer that 'only' charged for the part that fixed the problem... You've got a Gold-star dealer there, my friend!

I guess if you spend enough money on service and on cars over 25 years, they cut you some slack. Frankly, I've had good service from Porsche/Audi/VW dealers. In some cases, they've even left new parts (which didn't fix the problem) in the car at no charge, rather than take them out.

[bobetko]

Thanks Troy. I will try what you suggested.

[bobetko]

I got my Vag Com cable and connected my Passat today. Got readings from ECU, Auto Transmission and ABS breakes, everything else is saying no response from controller.

ECU reports:
18058 - Powertrain Data Bus: Missing Message from instrument cluster
P1650 - 004 - No Signal/Communication

Auto Transmission reports OK

ABS Breaks reports:
01203 - Electrical connection between ABS and Instrument cluster
31-00 - Open or Short to Ground


The thing is, VW service got me out with saying that TCM is bad (and that they are not sure what else). They never mentioned instruments and never ECU. VAG Com clearly says that everything is OK with TCM. I am planning to raise hell and demand my money back ($270 for their diagnostics). I am sure I won't get it, but I will complain...

Questions:
1) Can I trust VAG Com that TCM is good? In other words, could TCM be bad even though that VAG Com says that TCM is good?
2) Given the results I got on Vag Com, I don't understand how the guys at VW could missed it and put blame on TCM? It seems they didn't even look.
3) Any idea where to start to troubleshoot about this error with instrument cluster?
4) Is it possible to, somehow, shut down (removing fuses? :-)) this instrument cluster and then test car without instrument cluster. In my mind, instrument cluster should be of secondary importance and car should be working without it? Am I wrong?
5) Where the Instrument cluster is located and what does it look like? I looked at this guide http://www.impconcepts.com/vwpassat2...stallguide.htm and on one of the photos it seems that instrument cluster is actually the whole dashboard with all measuring instruments (speedometer and RPM) and displays. So if instrument cluster is bad, does the whole thing has to be replaced? How should I test this instrument cluster?

Thanks

[JayTheSnork]

if VAG COM says your TCM is good, I'd trust it. it is the best troubleshooting tool we have, and in many cases, better than the troubleshooting software the dealer has.

the instrument cluster contains all the dials and gages in front of the driver. I have heard of reports of the cluster going bad, but it is rare. I'd replace the cluster.

[bobetko]

I have checkd wiring around CCM and TCU. Everything looks nice and clean. Any idea why I am getting data only from 3 component: ecu, tcm and abs breaks? Nothing else.
When I turn ignition key, I hear sound like sparks (when you are making short circuit) from under the hood where some controller 4 brakes is. The same sound I hear when vag com is testing abs breaks. Could this be my culprit? Thx.

[z32drifter]

The immobilizer is inside the cluster, so if the cluster is down the car will crank but not run. Most of the time you will get your first symptom, car starts for a second and then stalls. The TCM will not cause the car not to start, you can disconnect it and still start the car. TCM failure will cause the trans to go into safe mode and the gear position display in the cluster will be the negative of the normal display. I think you may have a failed cluster. You can swap another cluster into the car to see if the communication issues are resolved. The car will not run until the cluster/immobilizer is addapted to the ECU and keys are readdapted to the new immobilizer.

[PZ]

Hopefully that noise is not sparks, but simply the ABS pressurizing and testing itself.

You can try unplugging the ABS harness and see if the instrument cluster faults will clear. For some unknown reason, ABS problems can cause the instrument cluster to go crazy.

[soundguybob]

I have checkd wiring around CCM and TCU. Everything looks nice and clean. Any idea why I am getting data only from 3 component: ecu, tcm and abs breaks? Nothing else.
When I turn ignition key, I hear sound like sparks (when you are making short circuit) from under the hood where some controller 4 brakes is. The same sound I hear when vag com is testing abs breaks. Could this be my culprit? Thx.

Unplug the ABS controller and see if you can scan the other modules. VAG-COM will have more modules listed than what will be present in your car. Try the CCM, it's address 46. A failing ABS module can kill communications with the other modules in the car. It's just a hunch at this point.

Also, do you have an aftermarket radio in the car?

[soundguybob]

HA ha, PZ and I were thinking the same thing... He just got his response in faster than me!

Also, the cluster contains the CAN gateway, which, from what I understand, is the intermediary between VAG-COM and the actual modules. If that's truly the case, then you won't be able to scan the other modules with the cluster disconnected or removed.

[z32drifter]

Any control module on the CAN bus can kill communications on the bus. You might try disconnecting the cluster and then recheck for communication on the bus. I think there may be more than one issue with the car. If the listed systems was all he can see it looks like the power train bus is up and the comfort bus is down. If the windows and other systems inside the car are working the CCM is up but the bus may be in single wire mode.

[bobetko]

Thanks guys. You know way more then I do. I assume claster you are talking about is instrument cluster? Is that right?
To answer all your questions...
I have original radio that came with car. Right now it is showing Safe message.
I tried disconnecting abs breaks, but couldn't read other modules.

My next step. I will remove instrument cluster and test car without it as you suggested. If I manage to read other modules then I should assume that instrument module is bad and I will order new instrument cluster, probably from ebay. So, if after that I get all good readings I will have to take car to dealer again to program new immobilizer (which is inside instrument cluster). Please tell me I got it all right. :-)
Thanks again. I'll keep u posted.

[z32drifter]

Yes I was talking about the instrument cluster, and the dealer will have to adapt the immobilizer/cluster to the ECM and the keys. Keep in mind if you put a used cluster in the car it will show the mileage of the car it came out of. You will have to inform the DMV when you renew your tags that the car is now TMU (total mileage unknown) there is normally an area to note mechanical failure of the odometer. If you purchase a new unit from the dealer they can adapt your current mileage to the new cluster.


There are a few other things you can try for free. One a "cap discharge" disconnect the battery like before but this time connect the positive and negative battery cables together. This will ensure that all the capacitors in the modules are drained and sometimes will revive a module. It's a slim chance and only a temp fix if it works. Two remove the cluster and clean the connections with electrical contact spray then reconnect the cluster. Again it's a slim chance and only a temp fix but could help you determine that the cluster is in fact your issue.

[soundguybob]

If you do need to replace the cluster, there are a few people around who can program it with the proper Immobilizer info, as well as correcting the mileage so it's remains true to the car. The dealer can only change the mileage if the cluster has less than ~100 miles on it. You can unplug the cluster and check for communications to the "comfort" modules in the car- you should be able to see the CCM and Radio. All of the power train modules connect to vag-com through the cluster, so you won't be able to see the ABS, ECU, TCM, etc.

When you checked the wiring to the CCM, did you just pull back the carpet and look at the harness, or did you actually peel off the bundling tape and separate out the wires? If you didn't do the latter, you didn't see all the factory made splices. I've seen several instances of the buries splices corroding, while everything looked fine with the harness bundled up.

Sounds to me like you may have more than one issue. Try the capacitive discharge that z23 suggested, he's been fairly spot on so far.

[bobetko]

Here is the update:

I received new (used) TCM today (cause I was told that old one was fried). Installed it and of course no change. Everything I described before stayed the same... dashboard and other things. The only change, now Vag Com is reporting new fault on Auto Transmission (before it was showing no faults):
18227 - Pressure Control Valve 2 (N216): Open or Short to Ground
P1819 - 003 - Mechanical Failure


Z32,
Tried cap discharge. Didn't help. Didn't see any changes (visual and on Vag Com)
Windows are not working.
Wipers, blinkers and lights are working fine which means what? Instrument cluster is not completely dead?

I removed instrument cluster today. Plugged Vag Com and situation was the same as before. I could still read Engine, Transmission and ABS breaks. Nothing else. Not a single thing from CCM, electronics or anything else.

After I unplugged then plugged back again, the whole instrument cluster started looking little different (almost like got alive again). Now the left display is showing time 12:00 (before it was showing one little line), right one showing mileage, one in the middle showing that imobilizator is activated, and also showing some other messages (water fluid, etc.) And all other image icons where lit (on). There is still little tiny clicking sound coming from cluster when ignition is on. Tried to start and of course it shut down immediately (as expected). Checked it again with Vag Com. No change. Still I can see only Engine, Transmission and ABS.

Questions:
1) Now, with instrument cluster removed, should I pay attention to CCM? How come none of other components are not reporting that there is no communication with CCM? Could CCM cause everything else to fail? Could healthy car run if you would disconnect CCM? (like z32 mentioned that car would run with TCM disconnected).
2) If I remove CCM, is there any other component (besides those that I can read now) that I should be reading?
3) What components I should be able to read on Vag Com to be able to declare that everything is good (assuming no error codes)?
4) Why is immobilizator activated? Is it cause I unplugged instrument cluster?
5) Should two displays on instrument cluster be off when I remove ignition key? Sorry. I simply can't remember what is normal any more.
6) Any opinion on these "Open or Short to Ground" faults?

Uh. Sorry. Too many questions...

The next thing I will do is to start checking wires all around. To my surprise, so far, wherever I looked everything was incredibly clean. No single traces of rust.

Thanks...

[soundguybob]

(random stuff as I think of it, sorry for the ADHD of this post!)

The cluster has nothing at all to do with the wipers, blinkers and lights, they will work weather the cluster is there or not, so it doesn't tells us anything about the cluster. The car won't start w/o the CCM in place. It triggers the starter interlock relays.

Did you try to read the CCM or radio (if it's stock) with the cluster disconnected?

Have you checked the fuses with a meter? (they can be bad and still look ok)

Did you unplug & reconnect the cluster w/ the battery disconnected? If not, pull the battery and do another cap. discharge so the cluster reboots fully. You didn't do anything that would've messed up the Immo system, short of one of the plugs on the back of the cluster being loose and either not "talking" to the ECU or the pickup coil. I've seen one instance of the cluster dumping all of it's programming and resetting to zero. Did the cluster maintain the mileage?

Since you've had water intrusion in the past, it's entirely possible that the CCM has gone bad. You haven't said weather you unbundled the harness or not when inspecting it. If you haven't, this is something you need to do! You simply will not see all the splices unless you separate out those wires. Note that there are a couple of splices that typically fall underneath the rubber boot going into the CCM's box, so you should check there as well. Also check the connectors going into the CCM if you haven't. Look over the connections in the kick panel, and make sure they are all clean and free from corrosion, etc. Being that the windows don't work, you either have a blown fuse, a bad CCM, or a broken splice in the harness. The splices are still the most suspect item IMHO.

You should be able to read the stock radio with the CCM disconnected.

The 2 little displays in the cluster will stay on, that's normal.

[bobetko]

I can't read CCM. You mentioned it is on address 46. I didn't try that. Tried clicking pretty much on most of the things in the Vag Com menus and nothing communicated back (radio, doors, steering wheel, HVAC, electronics1 and 2, etc..)

I think I tried reading radio (it is stock) while inst. cluster was disconnected. But I will try again.

Will check the fuses. I currently have issue with one of the fuses (one for horn) that is good, but it is sort of loose so my horn was working sometime, sometime didn't. It drove me nuts until I finally figured it out. There might be more fuses like that.

I'll check cables/splices and connectors today as well. As I said I was little bit discouraged from doing that before because everything looked very very clean.

Instrument cluster connectors look clean and firm (not loose). Also cluster still retains my current mileage.

Will try another cap discharge too...

Thanks for your help...

[soundguybob]

There's several modes in VAG-COM that simply aren't going to be present, or in some cases just not readable by the program. The CCM channel that's 40-something (I think it's 46) is the one that you need. Have you tried to just run the auto-scan? It'll search for all the modules that should be present and readable in the car.