Where is the CAN Gateway module located?

Geordi

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I've seen pictures of the possible location on MkV and up, but where is this elusive K / CAN gateway (Vag Com address 19) device located physically?

The following does not work in this 2003 Jetta Sedan:
Power Windows from switches inside the car
Sunroof
power mirrors
Horn
cruise control - multifunction steering wheel mounted
radio buttons on the steering wheel
Radio - which had been blinking the red light but would power on and work when you pushed the button on it... Now it is in safe mode and of course I don't have the code. It has never been moved or removed from this vehicle.

What DOES work:
Power windows from the outside key switch. Up and down. All 4 work and the sunroof closed itself at the same time.
Trunk release
fuel release
remote key for the doors

Codes have all revolved around data bus failure, from either the Can Gateway module or the instruments. New codes include "No communication" to the engine ECM and the transmission TCM.

No fuses are bad, including the two "hidden" fuses on the relay block and no change to the performance happens when disconnecting the driver's door or the 451 Multi function steering wheel module.

All of this suggests that the gateway that controls everything somehow is not working any longer. Where is the dang thing to try and replace it or swap it out?

I cannot connect at all to address 46 - central convenience. I have tried swapping the comfort module (I think this is the central convenience?) with the one from my Jetta wagon, also a 2003... No result. They have the same external part number.
 
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compu_85

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The gateway is part of the instrument cluster.

Can you access the steering column module in VCDS? Can you access the CAN gateway?

I'd suggest attaching a full auto-scan to your post.

-J
 

Geordi

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I can access the instruments, and I can access the gateway. I can no longer access the Central Convenience (46) which I am guessing to be the CCM. What is annoying is that I cannot access the CCM from my wagon either, and that is the same part number and SHOULD be a known-good.

All three fuses on the back of the panel are good, all fuses on the main fuse panel are good. Visually verified.

Power locks work, windows function from outside the car, sunroof does nothing (thankfully it is closed) and the car runs fine.

Radio which had been intermittently flashing the red security light while driving... Is now in safe mode and obviously has no communication.

Codes have not returned, but what was there previously was from both the instruments and the gateway - nothing from 46:
01336 - Data Bus for Comfort System: Faulty
01336 - Data Bus for Comfort System: Single Wire Mode

Is there supposed to be a particular wire or wires then leading directly from the CCM to the cluster? I've been looking at all the harnesses under there and pulled the cluster and haven't found ANYTHING that looks frayed or broken. I'm happy to go to a junkyard and get another CCM from an 03... But I'm not confident that is the problem since I could use the one from my wagon and it won't communicate either. Maybe I need to put that back in the wagon and check it with VAG.
 

compu_85

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That sounds like there's a short on the comfort can bus. I'd start by looking at the door harnesses. I recall someone having a similar problem when the fuel door popper shorted out.

-J
 

Geordi

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I've unplugged the driver's door at the wall - no change. Haven't done the same to the passenger door (which also got a new lock mech) but I have pulled the window motor connection, and that also was a no-change. Unplugged the rear door when I replaced the whole door (from an 03 b/c of some strange paint color fiasco - this car is supposed to be an LD7X, but each can I've gotten of that is BLUE when on the car!) and everything did work for a while... It just kept on dropping out for no reason at all.

I agree it seems there is a short or a broken wire, but I'm at a loss to figure out where.
Why would the windows still be able to be commanded up and down from the key, if the canbus wires are broken/shorted? Doesn't the signal to the windows travel the same wire?
Is that using the CCM as well?

I hate this electrical system.
 

Matt-98AHU

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The comfort system data bus *is* a separate data bus from the main CAN bus. The CAN bus is for intersystem communication between ECU, TCM, CAN Gateway, ABS, Airbag, cluster/immo etc.

The comfort system has its own data bus that communicates between all the "door control modules," which are integrated into the window motors and the central convenience module.

As compu_85 pointed out, the codes you have stored do say specifically that the problem is with the comfort data bus, so you need to be looking at wires between the CCM and all the doors. The most common failure is, once again as compu_85 pointed out, is wires breaking between a door and chassis, where the harness gets flexed repeatedly.

Once you wrap your head around the hows and whys of the system, you begin to like it as the computer diagnostics actually greatly reduces diagnostic time once you understand the system. AND, it actually has reduced the amount of wires that need to travel between the doors and chassis as so much switch information simply travels through the data bus, you don't need to have individual wires for every switch and signal in the door.

Signals from the driver's window switches that control all 4 windows, door locks, window lock out, trunk pop, fuel door pop, key in door switch, latch switch, lock position switch and the signal to tell the lock motor to lock or unlock--all those signals pass through the window motor/door control module and then get translated to the data bus. Without the data bus, each individual switch/signal I just mentioned would need its own individual wire between the door and chassis. Instead, they have a much shorter path, just to the nearest window motor, which then translates it over two data bus wires.

Anyway, long story longer, basically just do as compu said, unplug one door at a time, clear codes, make note of when the error stays off after unplugging what door. Once you've got it narrowed down, you can then start unwrapping the harness to find the break in the wires and go about repairing.

It's also possible that a window motor itself is at fault and taking down communication, but more often than not it's a broken wire.
 

Geordi

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Ok...

Well then, from the driver's door:
Trunk release works.
Fuel release works. (Thank god, b/c there isn't an emergency pull tab in the trunk!)
Locks work.

Windows and mirrors are non functional. So if all those things are supposed to be on the wires from the driver's door... Why no mirrors and windows only?
Why no radio?
Why no sunroof?

The radio HAD been working, now is stuck in safe mode, which suggests that whatever it is supposed to communicate with it is not able to. So is that the CCM or the ECM / instruments / gateway?

Car starts and runs so obviously the immo system can talk to the ECM and the gauges work.
 

JASONDEMEILLON!!!

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howsit guys im new to the forum would just like to ask I've just upgraded my ASZ'S turbo to a gt2256v turbo with the hybrid comp wheel. i have done my intake and a big front mount cooler. Currently I have a 63mm straight pipe but a lot of people have suggested that i convert to a 76mm downpipe. What would be the best option for the upgraded turbo. have not had any complications as of yet with the straightpipe
 

compu_85

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Why no radio? It gets its ignition state information from the comfort CAN. Why no sunroof? It sits on the comfort CAN too. The radio went into safe mode because it knows what car it's connected to based on CAN messages.

There are 2 different CAN busses in a Mk4... the powertrain CAN and the comfort CAN. The powertrain runs at a higher speed, and is separate from the comfort CAN for just this reason... so a comfort module wigging out can't make the car stop working.

Why does some stuff work and some stuff not? Perhaps some module is spitting a lot of garbage onto the bus, and those are the only messages that can get through? I wouldn't get hung up on it. Just find the error in the bus and everything should start working again.

-J
 

oilhammer

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There are just too many to list....
You could also possibly have an ignition switch problem, but it sure sounds to me like one of the doors' harnesses is messed up. It takes 5 min to disconnect all four door harness connectors and see what you can clear and get working again.

Obviously nothing in the doors will work at that point, but if everything else DOES, then you at least know you are on the right track.
 

Geordi

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Well, since I have the car in a narrow garage while working on it, I can only get to the driver's side doors. I've already tried unplugging the driver's door to no result, so I went ahead and unplugged the rear door since that is the only other door. Thing is, I have never messed with this door. The lock works, the window works, so why mess with it?

As soon as it is unplugged - I can connect to 46, the sunroof works, the other windows all instantly work from the driver's door... SONOFAMONKEY! W.T.F?

Codes in the CCM (46) say "implausible signal" from each of the other three doors. No codes in the instruments or the CAN Gateway.
The radio works again.
The sunroof works again.
The radio controls on the steering wheel work again.
The fuel door still works.
The trunk release still works.

So I pull the interior off, extract the wiring harness through the speaker hole and get all that sticky crap off... And find... NOTHING. Nothing broken, nothing looks funny at all.
Looks like I'm off to the junkyard for a power window circuit box?
 

Geordi

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2 hours later - not doing anything else to the car, not moving it... And everything is dead again.

Can't connect to 46 Central convenience. Codes from Gateway and Instruments:
01336 - Comfort Data Bus No Communication
01336 - Comfort Data Bus Faulty

Fuel door, trunk, and locks still function from driver's door. Sunroof, mirrors, all windows non functional again.
Radio is still working for the moment, but steering wheel controls do not.

So... Are we back to thinking the CCM has died somehow?
 

senso

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What door did you replace?
Did you already try to unplug that replaced door from the harness and see if anything changes?

Maybe the broken wires/shortcut are in the harness side, because if you unplug a door and it started working, look around that connector and respective harness that goes into the car.
 

Geordi

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Door that was replaced was the rear passenger door. This door now came complete from an 03 sedan b/c apparently there is some bizarre color that was only offered in 03 but was tagged with the same color code as everything else Platinum Grey Metallic from 9x-2010... Yet the colors in the cans are blue tinted and this car is definitely not. But this problem has predated that door swap. It started sometime AFTER replacing the lock mechanisms in both front doors - BUT those mechanisms have now been replaced again with fresh, and other than a bad contact switch (nice to see that the design hasn't improved)... No change. It either works or it doesn't - on its own schedule.

Anyway - no issues noticed in the harnesses on either side for the rear doors. The thing is, if it was a harness issue, why would it work suddenly when unplugging that door (ok, maybe jostling something)... But then die again with NOTHING MOVING not even closing the car door - sometime during a 2 hour wait?

I think the data bus stays awake when the car is off, b/c that is how the wireless remotes function, through the CCM. I'm wondering if maybe the bad data in the bus is from the CCM itself.

Edit: never mind about the coding, I was looking at the wrong field and I'm stupid.

However - the thing worked again today (still hasn't moved!) so I'm back in the waiting period to see if I can figure why it does this. Going to try again in an hour without opening any doors or moving anything - just to conclusively rule out wiring.

Thoughts?
 
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Geordi

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So it worked again this morning. Then an hour or so later, dead again.

I pulled it outside, unplugged both doors on the passenger side. No change.
Cannot connect to the Central Convenience (46).

Nothing works. Radio isn't in safe mode, but is flashing the red light while the engine is running.

How can this not be the module? A better question: When I swapped the module with the one from my wagon which also has 4 doors and power windows (but not a sunroof) why did that module also not communicate?

Where do I go from here?

Interesting observations: When I removed the CCM from my wagon just now, I noticed that the wagon's door security LED immediately started flashing. When I closed and locked the door of the wagon from the outside, everything functioned as expected and the door locked.
When I plugged the wagon CCM into the sedan, the module made a noise! It's never done that before, don't know what it was, kinda like a little buzzy sound. I had only plugged in the larger connector, the tan one. It was only a momentary sound.

I still have no functionality and no connection with Vag-Com when trying to connect to Central Convenience. No codes in gateway or instrument. power locks function. However I cannot program the wireless remote to unlock the doors. No response.

So this tells me that if there is multiple power lines to the CCM, then part of the circuits are not being powered, intermittently. Fuses are all good and they wouldn't be intermittent... So what else is there to check? I can't translate VW's horrible wiring diagrams for beans.

Help?
 
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oilhammer

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There are just too many to list....
Volkswagen has excellent diagrams.

You need to unplug ALL FOUR DOORS and start going from there. I would also check the wire connections behind the fuse box for anything that looks damaged.
 

Geordi

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I fail to see the difference, but whatever - here we go:

ALL FOUR doors completely unplugged. No change. No sunroof (since that is the only thing left besides the radio now) with the wagon CCM connected.

Reconnect the sedan CCM... And the alarm starts going off instantly. That was new. The key in the ignition does nothing. Have to pull the battery cable. Connect the battery again, all is quiet.

Still no sunroof, no connection via vag-com to CCM.
Codes in gateway and instruments are as before:
01336 - data bus failure
01336 data bus no communication

The failure code will not clear.

Battery is disconnected at the moment. I expect that when I reconnect the battery in a few minutes, the code will either be gone or will allow me to clear it. NONE of the wires look damaged behind the dash, and it is obvious that I am the only person to ever be inside this dash. Everything is still tied where it looks like it should be, and covered in that furry sticky crap that for some reason VW loves.

So what next? What ELSE can I disconnect? Remote key doesn't work, sunroof doesn't work, replacing the CCM doesn't seem to work.

I am seriously considering just setting it on fire.
 
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mebarinas

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hi,

all you need to do is check the comfort control module that is located under the carpet on the driver side, it is common to this module to fail due to moisture or water enter into the car under the carpet.

I bet that this is your problem, hope this could help.

regards,

Miguel
 

oilhammer

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outside St Louis, MO
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There are just too many to list....
hi,
all you need to do is check the comfort control module that is located under the carpet on the driver side, it is common to this module to fail due to moisture or water enter into the car under the carpet.
I bet that this is your problem, hope this could help.
regards,
Miguel

Um, no. :rolleyes:

You may try unplugging the radio and see what works. I wonder if something is shorting the CCM's controller bus (not the CAN bus).

Not sure if you can leave the one connector unplugged on the CCM and see if it can at least communicate on the CAN or not. I cannot remember which connector has which wires. I will try and look over the diagram when I get a chance.
 

Matt-98AHU

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If your car has steering wheel button controls, you could pull the multifunction steering wheel control module out from where it plugs into on the relay panel under the dash, re-assess. That's the only other thing possibly on just the comfort data bus system.

Door control modules, central convenience, radio and multifunction steering wheel control module. Apparently there's a telematic control module that could be plugged into the comfort data bus as well, but I can't remember seeing a North American market Mk4 vehicle with one of those.

The multifunction steering wheel control module will take up two relay sockets and have production number 451 printed on it.
 

Geordi

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I am not with the car at the moment (on another road trip and took the Jeep b/c I needed more space) but I do remember seeing that 451 module. Is that not directly addressable by the Vag-Com?

I will try pulling that next, then the only thing left plugged in should be the radio, which as far as I can tell has never been removed from the dash.
 

UhOh

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While you're waiting for an epiphany try removing the fuse to your ABS. You may also have ESP, so try cutting that out of the picture as well: might be tied to ABS, not sure.
 

JohnTF

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Geordi never can back with more info ? / conclusion ?

I can across this thread from a google search link , that started on youtube video , not sure but seems it could be of some use for either Geordi or anyone else in this rabbit hole ;)


My point of view is this could help to check for communication of points mentioned in this thread ?
 

compu_85

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I don't think the Mk4 has a gateway installation list function - it's only on the newer Mk5+ chassis cars. Someone might correct me though.
 

JohnTF

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A while back I did the scan , very limited list , as I remember only had a few on the list .
 

oilhammer

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There are just too many to list....
The 2000+ A4 cars have a CAN Gateway and CAN bus, but are not full CAN like the later cars. VAG sort of had a gradual soft rollout of that sort of thing. So no installation list or auto detect functions are available for them. You can auto scan them once you pick the correct chassis, but I find that to be cumbersome as it then looks for ANY potential module that COULD have been on the car, most of which we never even had access to in this country. Like telephone, navigation, trailer, etc. So it takes entirely too long.

The CAN Gateway, Immobiliser, and Instrument Cluster are three separate listed modules, but they physically all reside in the cluster (later cars' Gateways are a separate component under the dash.

In TDI trim, 2000+ cars, for the USA, these are the only modules you could have:

Engine

Transmission (if automatic)

ABS

SRS

Radio

Instruments

CCM

Immobiliser

CAN Gateway
 
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