VAG-COM no longer connects to A4!! K-line hung up?

[fritzner]

i am a fully registered TWIN-COM user (old school i know)
i was at the dealer on Friday to have a new key fob matched on my '02 A4 (B6) (i have the key tag, but not the SKC)..

the dealer said they could not connect to my car at all.. engine, cent. conv., anything..

i just recoded my tiptronic last wk, so i know it was working then.. and have connected many times in the past installing my RNS-E.. i havent done anything since then.. everything in the car works (rns-e, dvd player, video-in-motion, and all the standard stuff)..

i just went out to double check my vag-com -- AND IT DOESNT CONNECT!!
i tried my '00 turbo bug and it was just fine.. back to the A4 and it didnt connect!!..

vag-com gives serveral reasons, but the only one that seemed to make sense is the k-line could be hung up??.. not sure how that happens or how to fix it.. what happened ???

Things tried::
-- 4.7V between pins 4&7 with 1k ohm (with and and without the radio connected)
-- LED green when not plugged into PC..
-- Option -> Test = "Port Status: OK; Interface: Not Found!"
-- unhooking the battery for 15mins didnt seem to do anything..
-- working fine for years, nothing changed, nothing new, can no longer connect after dealer's failed attempt..

any ideas??.. HELP!!!

[kpatz]

You have an aftermarket radio, right? Those can hang the K-line if they're not hooked up properly. Did you splice in a connector when installing the radio? Check for shorts.

[initiala4]

He has the RNSE though. What color does the LED blink? Red?

[fritzner]

yes i installed a RNS-E (factory nav).. it has been in for 2 years and i have VAG'ed many times, so i am 99.9% sure it is hooked up correctly.. i took it out yesterday and double checked all the connections and they looked fine..

i checked the voltage between pin 4 & 7 with and without the radio connected with a 1k ohm resister and it was 4.7V in both cases..

but the LED on the interface was GREEN when plugged into the car with ign on, but not into PC..

thanks for the replies..

[fritzner]

i unplugged the ABS Controller and still can not connect..

still 4.7V between pins 4&7..
LED on interface still green when not plugged into the PC.. with or without the key on..

what's next??..

[Duchenbagen]

It may not be your vag com that is faulty. Do you have a cell phone update program on your computer like Active sync? If you do you may need to uninstall it off of you computer. I had this problem removed the program and all is well. I hope that this helps you out.

[fritzner]

the laptop is super old and doesnt have any automatic update programs (not even connected to the internet)..

it works fine in my VW.. so it must be a problem with the car..

thanks for the suggestion..

[fritzner]

i am ordering a bentley manual, but until can anyone tell me where any other controllers are??..
is there a schematic showing where they all are??..

i had ElsaWin, but i cant get it to install on my new laptop..

this sucks!!

[martini]

im having the exact same problem... never updated the pc.... its oldschool just like yours

[fritzner]

exactly the same as in -> you were able to connect and now you can not after the dealer tried??..

was there anything different??.. what have you tried so far??..

[fritzner]

just for the hell of it. i unplugged the battery over night (10hrs).. but, no luck -- still the same situation..

it definitely seems as though one of the controllers is actually bad.. unfortunately there is no indication which one.. no warning lights, everything functions perfectly..


-- as i am disconnecting controllers 1 at at time, are there any that i can not turn the key on to check the VAG-COM??..
-- should i just monitor the voltage between pin 4 & 7??..
-- do i need to have the key on to check the voltage??.. currently the voltage is 4.7V with or without the key on..

[kpatz]

Pull the lower dash panel out and check the OBD connector (the one you plug your VAG-COM cable into). Maybe a pin got bent or a wire came loose inside it.

[fritzner]

Maybe a pin got bent or a wire came loose inside it.

before i tear my entire car apart disconnecting controllers, that is what i am going to try next..

Uwe Ross suggest i try Options -> Test with a HEX interface as it is more intelligent..

so i met up with HEX-USB user Dan tonight (thaks alot man)
with the TWIN-COM
Option -> Test = showed
"Port Status: OK
Interface: Not Found!"

with the HEX-USB
Option -> Test = showed
"Port Status: OK
Interface: Found
Not connected to car"

i also had a chance to talk to the shop foreman at my local dealership (Great guy).. he thought since there werent any warning lights and everything seems to operating properly and since i checked the commonly problematic controller, there was a very good chance that it was diagnostic port itself or the wiring within a few inches from the port..

the idea that is the diag port seems to be consistant with the HEX test.. when we did Option -> Test on Dan's MKV GTI it said:
"Port Status: OK
Interface: HEX-USB
K-line 1 = OK
K-line 2 = OK
CAN = OK"

so it seems the diag port or nearby wiring is winning the poll, "what is F'ing up my VAG-COM connection"..

wish me luck, thanks ..

[fritzner]

I CAN CONNECT AGAIN , but there still may be a problem
I found that the diagnostic fuse was blown.. i replaced it and i can connect and clear code all that fun stuff!!..

a blown fuse was one of the 1st suggestions along with the aftermarket radio, but i was confused.. i didnt realize there was a fuse for diagnostic power.. the interface LED was green.. and from the aftermarket radio page i thought the suggestion was to check the fuse in the interface -- but that refers to the old interfaces..

though everything seems to be working now, there is still voltage between 4&7 (k-line), but it doesnt seem to be a problem..

thanks for everyone help.. i will let you know if i have any more issues..

[martini]

I CAN CONNECT AGAIN , but there still may be a problem
I found that the diagnostic fuse was blown.. i replaced it and i can connect and clear code all that fun stuff!!..

a blown fuse was one of the 1st suggestions along with the aftermarket radio, but i was confused.. i didnt realize there was a fuse for diagnostic power.. the interface LED was green.. and from the aftermarket radio page i thought the suggestion was to check the fuse in the interface -- but that refers to the old interfaces..

though everything seems to be working now, there is still voltage between 4&7 (k-line), but it doesnt seem to be a problem..

thanks for everyone help.. i will let you know if i have any more issues..

what fuse number was it.... im assuming its in the standard fuse panel?

[fritzner]

what fuse number was it.... im assuming its in the standard fuse panel?

#12 is actually labelled "diagnostic", it is in the standard fuse panel inside the drivers door..

[kwan]

I was just gonna post saying "check the fuse" while reading the posts. Had a friend during training go through the same headache you did. Spent about 5 hours overthinking the process and we asked if he checked the fuse...doh!

[martini]

my fuse was fine, and i disconnect the battery to no avail

im still stumped on this one

[Mumpz]

'02 A4 with the same problem, so I'm reviving this thread.

I will try all the things posted above and hopefully I'll have some good news and a solution to post!

[EuroxS4]

Since we are bumping ancient threads, also know that a failing abs module will not let you connect to a vehicle, also note that aftermarket radios sometimes cause the same issue.