CAN Databus Issues - very long

Discussion in 'Multimedia' started by pokrovsky, Feb 20, 2015.

  1. pokrovsky Member

    Hello,
    I did a lot of search and saw some similar problem reported but could not find the solution unfortunately.
    I have a databus error in my setup after recent retrofit work.
    01305 - Databus for Infotainment
    004 - No Signal/Communication - Intermittent

    Here is where I started:
    2002 allroad with Symphony II, Bose, OnStar.
    Over the course of several years I did the following:
    - retrofitted the OEM BT module in place of OnStar - everything worked fine (several years)
    - retrofitted Dension Gateway 100 iPod interface. First simple version and later replaced it with CAN version. Everything worked fine for several years. Song info on DIS was nice
    - retrofitted OEM Sirius Sat radio. Wired it using the stock CDC harness in the trunk, preserved Dension by splicing the Audio based on Teddy's and NSX jr write up. Everything worked fine.
    - retrofitted shark fin antenna from 2005 allroad
    - retrofitted RNS-E with universal wiring harness adapter. Ran a GALA to the back of the cluster, ran RFSL wire to A-pillar (although I heard it's not necessary since my RNS-E unit is 193B)
    - replaced old Sirius unit with the newer Sirius/XM module (single FAKRA, used the dual to single FAKRA y-cable)
    - then I had an itch and wanted to get an CAN AMI to replace the Dension Gateway. Since that was also gonna free up the CDC interface that Dension was occupying I decided to retrofit the OEM CD Changer

    - I did direct swap of Dension for CD Changer (built a custom harness and tapped into the appropriate wiring where the original CDC connectors were supposed to go) and built a custom AMI harness (very simple, 3 audio leads to 32 pin connector and 4 more wires directly to CAN and power/ground)

    What resulted in this work is the communication issue with Sirius, I can intermittently connect to it via VCDS but the connection is bad and intermittent and the module itself gives a message to RNS that this is simplified installation and tries to initialize to no avail. AMI works as an AUX but not recognized by RNS-E (I can't recode RNS-E since I need to downgrade the software from my current version 230, but that's the separate issue). CD Changer is powering up and lets load CDs but is not recognized/seen by RNS-E - I suspect due to CAN comm issue with SAT.

    To understand the situation a little better. I checked and rechecked the wiring, I even totally re-wired, chased every wire/pin from RNS-E to the car harness and got rid of all the old connectors and wired RNS-E quadlock directly to the car harness.

    As far as CAN: VCDS sees the phone (OEM BT) - no problems/codes. DIS sees the phone book, MFSW works and operates phone just fine.
    SAT displays Initialize/CAN on the DIS
    AMI (in current config as AUX) also displays AUX on DIS

    Any pointers to troubleshoot the Databus issues?

    Thanks!
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    PetrolDave Super Moderator

    The CD changer doesn't connect to the CAN bus and the RNS-E will communicate with a CD changer even when it's not coded for a CD changer, so the RNS-E has a problem is what I would suggest.

    I don't think there's a CAN bus problem because if there was then VCDS wouldn't see the BT module, neither would the DIS get the phone book from it.

    I'd unplug the Sat radio and the AMI and start working out the minimum setup that can communicate, then start adding things back on until it stops working again.
  3. pokrovsky Member

    I've done some more experiments: disconnected both AMI and Sirius/XM and still had Databus error code with VCDS , so I'm afraid I fried the CAN-bus infotainment module in the instrument cluster. Is it possible?
    I thought that perhaps one or both of the CAN-L and CAN-L from the back of the RNS-E to the cluster is faulty so I ran a separate line to test it and same thing, still same code. MFSW still controls the RNS-E just fine (FM/AM), Phone responds to the buttons on the steering whell as well, so I'm really stuck.

    I went through so much pain custom building the wiring harness to get rid of all the adapters/connectors between old Symphony II and new RNS-E quadlock and looks like did something during this process that I can resolve now. In order to go all the way back it will be insane amount of work but doable. I just don't want to go through such exercise just to figure out the problem is in the cluster and not in the wiring.

    Why the CD Changer does not work is another enigma. That should be pretty straight forward, just power, acc, ground, 3 audio lead, data in, data out and data clock, how could I screw this up?
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    PetrolDave Super Moderator

    I very much doubt the CAN bus is fried in the cluster, if it was then you wouldn't be able to control the RNS-E with the MFSW - as that communicates using the Infotainment CAN bus.

    One thought, I do remember it being mentioned on here that not all the 193 RNS-E versions would accept and use the A6 version of the CAN bus protocols. Maybe that's the problem here?
  4. pokrovsky Member

    Thanks PetrolDave for all your pointers and thoughts.
    The issue is I didn't have any of these problems before my latest attempt to add AMI. And the RNS-E was always coded for an A6 with no issues.
    I've disconnected everything as far as peripheral equipment and now it's just the RNS-E plugged into the car and I still have the error of Databus communications being intermittent (01305, it changes the fault status code occasionally, the sequence of zeros and ones).
    Block 17 also shows the error of intermittent communications with radio, no other codes/issues there.

    Another peculiar thing is the behavior of the BT Telephone module. It seems to work/connect all the time but more often than not it looses the connection with RNS-E but not the instrument cluster (BT icon and signal strength disappears from RNS-E lower row screen) but the phone still works (although RNS-E says it's not available).

    Is there a module inside the RNS-E responsible for CAN-bus communications? can that perhaps be faulty?
    MFSW commands work all the time so that puzzles me even more!

    I can't believe I messed this up so badly! all because I wanted slightly better iPhone integration with AMI than Dension was providing me with Gateway and everything was working perfectly fine. Now I don't have SAT, no Dension, no CD Changer, no AMI, phone is glitchy, etc!

    Thanks very much.
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    AudiA4B6US Super Moderator

    CAN can be very picky about noise on the wires, especially if split incorrectly. CAN is a bus network but many retrofits end up being more like a star than a bus. While a star may work, you may also get unexpected results.

    I haven't had any issues when bench testing the RNS-E and various modules, in a car it's a whole different story. I would recommend to spend some time and start from scratch, disconnect the AMI and SAT (ideally at the RNS-E) and see if there are any communication errors between the cluster, the RNS-E and the phone interface. If you retrofit the phone interface using the Onstar CAN wires you should be fine. And if you retrofit the SAT receiver via the Audi pre-wiring you should be fine. If you ran your own wires from the dashboard to the trunk then make sure that they are twisted correctly and not near power wires. As Dave said, the CD changer has nothing to do with CAN, if it's not detected then it's too old for the 2010+ RNS-E or the 3-wire data/clock/enable has an issue. Even if the SAT receiver is in-between the CDC and the RNS-E, the RNS-E should still see the CDC if the SAT receiver is unplugged (no audio though without SAT receiver).

    If the RNS-E and phone interface are happy talking to the cluster, then add the SAT receiver and see what happens. And if that works add the AMI.

    I'm using a SEAT RNS-E PE in my 2004 A4 with the Audi phone interface (upgrade from OnStar, original location under passenger seat), AMI (Kufatec Quadlock harness), Sirius (Audi pre-wiring in the trunk) and Dice (emulating CDC, no CAN) without any issues. In my car I have the original ISO connectors going into the Kufatec ISO to Quadlock adapter to Kufatec AMI Quadlock adapter to the RNS-E. The AMI is at the end of the CAN bus coming from the RNS-E and it's the only device that I have added to the CAN myself. SAT and phone are using Audi's CAN wires.
  5. pokrovsky Member

    Thank you AudiA4B6US.
    How do you fit all these adapters behind the RNS-E??? the reason I got rid of all of them was to save space and be able to slide the RNS-E to the cage without jamming all that stuff too much and it is still tight!
    I'm thinking of doing the reverse procedure now and just get all the Kufatec adapters and see if that works.
    I built the AMI harness myself and added a twisted pair for CAN but it goes along the power/audio wires, is Kufatec harness different? can that cause CAN interference issues?
    What happened to my Sirius is a mystery as it was working fine for 3 years with the wiring in the trunk (original harness was for 13 pin mini din round connector and I spliced (used 8 wires from the original cable to run 3 audio to, 3 audio from and 2 CAN wires), I ran power to SAT module separately from the Bose amp in the trunk. Dension Gateway (CAN version) was plugged behind the RNS-E with it's original harness with the exception of 3 audio wires were interrupted and spliced with 6 audio leads (to/from) of the SAT trunk cable.
    So my logic was following: replace Dension with OEM CD Changer (should have been straight forward), add an AMI (uses 3 audio connectors in the 32 pin, 2 power wires directly into the D connector of the RNS-E and 2 can wires spliced into the existing harness). For some reason this turned into this nightmare.
    I cut all the ISO plugs (1 wire at a time and used AUDI mini crimp butt connectors to connect them to the appropriate leads on the RNS-E quadlock)

    How to make sure the RNS-E isn't damaged?

    Should I try a different CD Changer and if so which model should work with 193B unit? Mine is 8E0035111 (no letter at the end).
    I can probably live without it (although I went through some serious effort of cutting/modifying my glove box for it), I can perhaps used this space/cage now for AMI (which I had to take out of it's mounting bracket)

    Thanks again for all the support! this forum is full of invaluable information and people and true enthusiasts!
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    AudiA4B6US Super Moderator

    The CD changer must be at a certain firmware version to work with he RNS-E (that was at least true for the first gen RNS-E). CDCs with part num 8E0 and manufacturing date late 2004 should work. 8E0...D should work also. I can't remember if the 8E0 changer without index is supposed to work.

    If you would be in Chicagoland I would say stop by on the weekend and we connect your RNS-E to my A4 and see what happens. If you used the CDC harness between the head unit and trunk for the SAT radio then that might be causing errors on the CAN. The CDC harness did not contain properly twisted wires for CAN as far as I remember and it's very long. Even though it may have worked, a little change to the system may cause everything to act weird. Also, if you connected both the SAT receiver and the AMI to CAN at the RNS-E then you have a star and not a bus. You would need to connect the RNS-E to the CAN coming from the car, the AMI to the CAN at the RNS-E and the SAT receiver to the CAN at the AMI.

    As I said before, I would start with a small setup, just RNS-E, phone interface (because it's using the Audi wiring) and instrument cluster. Then connect the AMI (because it's relative close to the head unit and it should be easy to extend the CAN from the RNS-E to the AMI. Short CAN cables (a few inches) should not care too much about the twisting, longer cables (especially the one between the head unit and trunk) should follow the rules to avoid interference.
  6. pokrovsky Member

    Unfortunately I'm not anywhere near the Chicagoland, I'm in Houston, Texas area. I'll try to find somebody with similar setup to test my unit.

    Would you please clarify star vs bus connectivity? Before when everything was working fine I just used wire taps and connected CAN wires from SAT to the ones going from RNS-E to the car harness. I've read enough examples and for some reason thought it's ok to just combine all CAN H in a bundle and all CAN L in another bundle and connect to the car CAN H/L wires. In my case there should be 3 of each (RNS-E, SAT and AMI) - does this create an interference?

    With everything disconnected from the CAN (other than RNS-E), why do I still have an infotainment databus error? Is it possible I pinched the harness that goes to the OnStar perhaps? this would be my only alternative thought
    • Premium Supporter

    AudiA4B6US Super Moderator

    It's almost 10 years since I played with the RNS-E and CAN stuff. I can't find those posts anymore but there were several with guidelines from Audi on how to repair CAN wires. They went so far saying that if splicing is required, the connections on the high wire and low wire should be 2-4cm apart to avoid interference. There were also posts saying that even though no device is connected, loose CAN wires would act like antennas and messages would get lost or scrambled so that the receiving device won't understand them anymore. The infotainment CAN is much slower than the power train CAN though (100kbit vs. 500kbit) but interference could still be an issue. So even if you disconnect the devices, the wires may still cause an issue. I can't remember were I read the star vs. bus topology, too long ago. It might not be that critical though since in my A4, CAN goes from the cluster to the RNS-E and from there to the AMI but the phone interface (under the passenger seat) and SAT receiver (in the trunk) are connected somewhere else to the same CAN. So my RNS-E and AMI are on one arm of the star and it still works.

    The best option might be to test the RNS-E in another car and see if it can talk to the instrument cluster.
  7. pokrovsky Member

    A little follow up:
    I rebuilt the entire wiring adapter one wire at a time and even ran a separate twisted pair from behind the cluster to make sure.
    RNS-E is having issues communicating to the instrument cluster and also distorts the CAN signal for SAT module. Infotainment CAN bus works fine between MFSW, Telephone and instrument cluster. RNS-E also responds to all the commands from the MFSW but has zero communications with Telephone (aside from mute function and mute icon on the screen) and very flaky communications with SAT module.
    SAT module is difficult to access via VCDS although possible (if it can go through multiple comm issues) - I ran a separate twisted pair to the back hatch area where the SAT module resides to test and still same effect, so i'm pretty convinced that RNS-E is causing that. Unfortunately SAT module cannot be accessed via VCDS with can totally disconnected from the RNS-E.
    I'm running out of ideas of how else to trouble shoot the CAN network and RNS-E unit. I might be able to find somebody locally with similar car to plug my unit there and see if it can communicate with the cluster.
    Any other suggestions?

    Thanks very much for the help and support
    • Premium Supporter

    AudiA4B6US Super Moderator

    Not really, all I can say that I have a 2010 Seat RNS-E PU with AMI and "2 antenna" Sirius tuner plus a 2007 Audi phone interface in my 2004 A4 and it works just fine. RNS-E harness is ISO - Quadlock adapter, AMI Quadlock adapter, RNS-E with Sirius and Phone using the OEM wiring. No comm issues with VCDS Hex-CAN USB and Macbook Air with XP running in VMware Fusion. VCDS should find the SAT tuner on address 0F.

    Sounds more and more like a defective RNS-E...
  8. pokrovsky Member

    Thanks again for your reply, AudiA4b6US!
    Just to follow up, the issue has been resolved (almost, a little bit left).
    Apparently what was causing the glitch in the infotainment CAN traffic was the MFSW relay #618. Why it started not immediately I have no clue, all I know that i fixed the CAN problem by replacing that relay with the 616 version. 618 version of the MFSW is the one that is used on the cars with 6 radio/telephone control buttons, heated option for the wheel and tiptronic buttons, 616 - is the equivalent for a 6 speed manual cars or the tiptronic cars but without the steering wheel shifters.
    Here is some background:
    I converted my allroad that was TipTronic car to 6 speed about a year ago but the steering wheel stayed unchanged and that wheel had tip buttons. I wanted to get rid of them and found a brand new MFSwheel but without tiptronic buttons and replaced it. It was going on when I also took on the AMI retrofit and I just didn't put these thing together.
    Now after replacing that relay I have perfect communications between all the modules (SAT, AMI, Phone, RNS-E, Cluster, MFSW). The only issue is that I had to re-code my RNS-E from "05" an 4B A6 mode to something else in order for it to accept the code for AMI and now can't code it back to A6. Because of that my GALA connection to the cluster isn't properly working.

    I read that I need to downgrade the software to 0150 in order to be able to code the RNS-E to an A6 but my attempts to do so failed thus far.
    So everything works, just the NAV is not as smooth as it's supposed to be with properly connected wheel signal, which I hope to resolve through coding one way or another

    Thanks again for all the help!

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