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  1. #11
    Join Date
    Jun 2005
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    Aberdeenshire
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    1,961

    Default Re: Have you ever had CAN bus issues?

    There is no CAN at diagnostics port but the control units themselves are connected in a CAN network.

  2. #12
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    52

    Default Re: Have you ever had CAN bus issues?

    Thanks Tolsen. I was wondering if anybody has an actual wiring diagram for the CANbus? I've pulled some info from Evilution and had a quick go at it. A couple of issues though - the data an fq101 is different. Also I have a nagging doubt with my own car in that the engine cutting out and one line on the dash is intermittent. So far it has cleared itself by switching off the ignition a couple of times then it will start again. I would guess a wiring break would be more dramatic and need a tow home.

    I think the ABS should be on the diagram somewhere, but I don't have the pinout for it.
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    Last edited by Smartysmartface; 18th July 2018 at 10:52. Reason: Missed a bit...

  3. #13
    Join Date
    Jun 2005
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    Aberdeenshire
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    1,961

    Default Re: Have you ever had CAN bus issues?

    Quote Originally Posted by Smartysmartface View Post
    I think the ABS should be on the diagram somewhere, but I don't have the pinout for it.
    I think ABS in your case is ESP. Of course since mine is old from 2002 before ESP, mine only has ABS.

  4. #14
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    52

    Default Have you ever had CAN bus issues?

    Iím not going to tempt fate, but it might be sorted. I started checking the CANbus wiring. Pulled the connector from the SAM and speedo and they were okay. I tried checking the SAM to ECU but couldnít find the right pin combinations. I pulled the connector from the passenger seat ESP module and broke the connector getting it apart. It was fitted cockeyed and I couldnít get it to release, although it came out readily once it broke! I checked the SAM PCB for dry joints (none found) Then I checked under the car and found the rear tray piled high with acorns. Some little furry buggers must have been living there. I thought great, they will have chewed some wording and thatíll be the issue. But these ones obviously prefer acorns, because there was no damage. In fact thereís only the ABS sensor wires with three cores that go to the ABS pump and all were fine. What I did find was the wiring to the cycle valve was bare and could have been shorting. Also the black/red pipe from the turbo to the boost solenoid was broken off which I thin was causing limp mode unless you drove very carefully. So I clipped and managed to fit the pipe and I replaced the bare wiring.

    The car now seems okay, but I donít want to say itís fixed, just in case! Which was the offending issue, Iím not sure of. I was getting CANbus timeouts from the ESP, so perhaps the wonky connector...?

    One thing I have found is that the CANbus wiring diagrams out there appear to be for the 600cc version as mine is different. Iíll see if I can draw one for the 700cc ESP version.

    /G


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  5. #15
    Join Date
    Feb 2006
    Location
    Hampshire
    Posts
    1,075

    Default Re: Have you ever had CAN bus issues?

    From experience most CANBUS issues are caused by issues in the SAM. Either damp/water ingress or dry solder joints.

  6. #16
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    52

    Default Re: Have you ever had CAN bus issues?

    So, not wishing to have spoken too soon, I had clearly spoken too soon! Still cutting out and flashing up the one bar indicating a CANbus error. To re-cap, I have cleared up many other faults (reluctor rings, a vacuum pipe from turbo to waste-gate actuator and damaged wiring) which could also cause issues with warning lights, dropping into limp mode etc. But the problem is still there. Can drive for 20 miles and then other times, 500 metres. Engine cuts out sometimes stopping in gear which is a PITA. switch ignition off and on again and usually get the one line. Keep locking unlocking moving from N to R and ignition off and on and after a few goes or a minute or so, the display will show N or whatever gear is selected, the transmission jumps into life and it will start and run. Sometimes for half a mile, other times a few miles.

    I've checked the CANbus wiring many times now. Also any other wiring I can get to that even looks like it isn't perfect. I've had the SAM, ECU and speedo apart to visually inspect, but all seem good. I swapped the Yaw module under the seat (Mk7 model) as I had a spare. I also swapped the engine earth and battery earth leads out in case it was an earthing problem. Still no change.

    Having worked in Avionics a long time ago, I tried heating the SAM then the Speedo and then the ECU in the oven to 50 degrees, then repeated the process only I put them in the freezer. That usually turns any intermittent electronic fault into a constant fault, but all failed to make any difference.

    The only thing I can think is that I believe it cuts out more frequently when the engine has been run then left for a few minutes. Could the crank position sensor failing show up as a CANbus fault?

    Other than that, the front engine mount is knackered and so the engine thrashes about when changing gear so perhaps there's some wiring down the back of the engine that's catching on something?

    I did find a thread which sounded really similar: http://www.smartz.co.uk/archive/index.php/t-17680.html I read this huge thread all the way to the end, hoping for a happy ending, but there was none! I'm determined to fix this, it can't be too far off now, there's not much left!!

    Crankshaft position sensor perhaps? Or wiring down the back of the engine somewhere (to alternator perhaps?)?

    Any other suggestions at all? Has anybody had anything similar and fixed their own CANbus problem?

    - Gordon.

  7. #17
    Join Date
    Sep 2016
    Location
    Burnley
    Posts
    510

    Default Re: Have you ever had CAN bus issues?

    I have a spare gear lever you can try if you want to pay postage for it there and back once you have finished.

  8. #18
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    52

    Default Re: Have you ever had CAN bus issues?

    Thanks for the offer Mjolinor, very generous. I may well take you up on that. At the moment though, I am still thinking it is something totally trivial as I have cooked and frozen all the electronics and didn't manage to force a hard failure which was a great surprise to me. So it could still be a dodgy connection somewhere. If only I knew where...

  9. #19
    Join Date
    Jul 2005
    Location
    over here
    Posts
    13,577

    Default Re: Have you ever had CAN bus issues?

    Quote Originally Posted by Smartysmartface View Post
    So it will be a dodgy connection somewhere.

    FTFY
    fq101.co.uk

  10. #20
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    52

    Default Have you ever had CAN bus issues?

    Another update. Sadly itís still not fixed. Checked out the wiring again. All making good contact. Got myself a replacement ECU, cloned it to mine. Really thought it was fixed but it stopped again yesterday. I had a hunch that it is more reliable when the weather is colder and that warm sunny weather was a contributory factor. Traffic definitely is.

    Next plan is to try and trace the actual wiring to check for physical damage. So I have a question - where does the wiring loom physically route between the SAM, the Speedo and the ECU. Looks like it goes from the SAM up through the dash to the speedo, but where does the connection go between SAM and ECU. Maybe thereís a bulkhead grommet missing and a short occurs now and then?

    Only other thing I might try is to get a cheap speedo and clone that. Does anybody know how to clone the SAM? That would rule out all the electronics (yaw sensor already swapped, as well as steering wheel).

    Iím getting very close to giving up and scrapping it. Which would be a real shame. 🙄


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