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Bcm issue

Discussion in 'VY Holden Commodore (2002 - 2004)' started by yz300, Nov 30, 2019.

  1. yz300

    yz300 Member

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    Hi everyone. I.ve got an 03 vy berlina sedan. I had srs, abs, aircon and trac control alarms going off like mad and often the buttons on the key don.t unlock the doors or boot, so i took it to the mechanic. After quite a bit of money and buying an ecu/bcm/key combo from the wrecker to keep costs down and replacing burnt relays he thought he.s solved the problem. He said his scan gun said no communication from bcm. It was awesome, until today. I put the key in and before i.d even started it i had all those alarms come up again except the aircon, the door lock buttons on the key weren.t working properly either until i pulled the bcm fuse (the 10amp one under the bonnet) and put it back in. I heard a noise and thought hmmmm. Put the key back in and no codes. Could this be as simple as replacing the key battery or could it be a dicky wire from the bcm to its fuse or the bcm to the ecu? Is there anything else it could be? Input will be appreciated, thanks Gus.
     
  2. krusing

    krusing Well-Known Member

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    It sounds like either a Alternator issue, like over voltage.
    or earthing issue with all the symptoms happing all at the same time, I read somewhere there is a Earth terminal that can come lose, near the alternator, and/or adjacent the BMC.
    Where he said no communications from the BCM, was he unable to read any codes at all ?
    I see your in Victoria, but where ?,
    Because there maybe some close by that is a member of JC's that maybe able to help.

    PS: I helped another JC's member Nealeyboy not long ago with a similar issue, and it was a Alternator issue,
    If you in close proximity to me, I will PM you.
     
    Last edited: Dec 1, 2019
  3. yz300

    yz300 Member

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    Wow thanks for the detailed reply. I think he was able to see other codes but loss of communication with everything it.s meant to came up too. Even when the car is off and i try to unlock the doors with the buttons it sometimes doesn.t work properly, just incase this might mean something. I live in corio, near geelong. Thanks again hey!!
     
  4. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Try pulling off the ABS connector then see if it fixes the problem. Doesn't sound like a mechanic job more like a auto electrician. Check all your earth wires around the battery to chassis, test your battery voltage with it running with a multimeter.
     
  5. Lex

    Lex Well-Known Member

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    Do you have abs? If not alternator.
     
  6. yz300

    yz300 Member

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    Thanks for your reply,
    What.s the highest voltage it should be?
     
  7. yz300

    yz300 Member

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    Yeah its got abs
     
  8. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Any where from 13.8 to 14.2 no higher than 14.8. Like was said if not your Alternator try removing your ABS harness under the hood see if that sorts things out.
     
  9. yz300

    yz300 Member

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    Hi thanks again for your reply. Can you tell me where the abs harness is by any chance? I think i saw it and had a little try the other day but couldn.t work out how to do it without breaking it? Gus.
     
  10. Lex

    Lex Well-Known Member

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    Here is a video that will show you where the abs module is, & how to disconnect the harness.
    Hope it helps.
     
  11. yz300

    yz300 Member

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    Awesome. Thanks for your help. Mightn.t get to it super soon but to have all these ideas of things to check is awesome!! Gus.
     
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  12. yz300

    yz300 Member

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    I changed the left engine mount a few weeks ago, the manual said to disconnect the earth on the battery so i did. Might i have made another wire worse than it may.ve already been or something when i jacked up the engine?
     
  13. yz300

    yz300 Member

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    Hi thanks again for trying to help. I got 14.3 at idle on the battery.
     
  14. Lex

    Lex Well-Known Member

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    When idling, & multimeter (=mm) is reading 14.3, when giving a rev, does the reading from the mm stay steady, or does it give a higher reading? If the reading is higher the alternator is cactus.
     
  15. yz300

    yz300 Member

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    The terminals under the slide out plug looked a bit dirty so gave them a clean. We.ll see. Thanks for the vid, will be useful if i go down that road. Makes it simple. Gus.
     
  16. yz300

    yz300 Member

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    Didn.t rev it but deff will and will report. Wouldn.t a fault come up if it was no good? I had one years ago and put new brushes in and the warning light went away. Thanks again.
     
  17. yz300

    yz300 Member

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    I revved it up and the multimeter stayed at 14.3. I did notice there's a little plastic shield on the alternator where the wire from the battery comes to and the shield is broken. Might this affect anything? Thanks again
     
  18. Lex

    Lex Well-Known Member

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    If the shield is broken enough it will cause shorting out.

    Its not the alternator causing the problem, looks more like the abs, or wiring?

    You have any hole saws? If so you can make a shield to replace the plastic one. I think the plastic one is called bakerlite?
     
  19. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Question now is was it doing it before removing the battery to do engine mount?
     
    Last edited: Dec 2, 2019
  20. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    03 vy need a tech tool not a scan obd2 tool which wont work, also did you get the right bcm there are different levels, you need to match the number on your original box.
     

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