2002 Suburban Passlock problem

Projects & Restorations

  1. Justwondering

    Justwondering Well-Known Member

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    I do have side terminals that have been on and off a dozen times now.
    I'll recheck for corrosion under the insulation.
    thanks for the advice.
    JW
     
  2. Camtron

    Camtron Well-Known Member

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    If it has the red rubber boot formed around the end of the cable/terminal connections, peel that back and double check underneath it. Can’t hurt.
    Good luck.
     
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  3. Mikes5thAve

    Mikes5thAve Active Member

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    I don't know much about what you bought to bypass it but it should have bypassed all that sensor stuff at the ignition and made it all redundant.

    The only other failure point is the vats unit itself.
    With all the strange light flashings going on since you installed the bypass it sounds like it's something about that which the security system doesn't like. Or the security unit itself is messed up and that's what's causing all the problems.
     
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  4. Justwondering

    Justwondering Well-Known Member

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    This is the video I'm going to follow and see if there is a corrosion problem:

    JW
     
  5. Justwondering

    Justwondering Well-Known Member

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    Maybe after 200,000 + miles and all that vibration
    AND
    12 straight days of rain with humidity that comes with it ..
    MAYBE
    I'll be lucky and its just a light film of corrosion.

    JW
     
  6. Justwondering

    Justwondering Well-Known Member

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    Well as of 9:30pm, Jack, the NewRockies Bypass Module support guy bailed...
    quote:
    Jack, Mar 22, 10:13 PM ADT:
    It appears you have other issues with the power distribution on this vehicle
    Thank you,
    Jack
    unquote

    ouch!
    Looks like I'm on my own until I figure out 'the power distribution on this vehicle'.
    lol
    beginning to wonder if it was the passlock problem at all or if this is truly 'a power distribution' problem.

    too funny..
    JW
     
  7. Justwondering

    Justwondering Well-Known Member

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    I very proud to say that I can now remove the key cylinder from a 2003 Suburban, clean the contacts on it and replace it -- successfully.

    In no way did it help the situation with the anti-theft device, but its much cleaner now!

    JW
     
  8. BudW

    BudW Moderator Staff Member

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    That is both good and bad . . .
     
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  9. Justwondering

    Justwondering Well-Known Member

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    Today ::
    1. no corrosion around any of the electric lines into or out of the battery
    2. I can short the starter relay at the fuse box in the engine compartment and the starter chugs, so I know its good
    3. I found the splicepack 1 (sp205) -- oh lawdy, how in the heck to get to it?? Looks like I need to remove the driver seat.
    4. Did check the electric lines under the driver seat and none of them look compromised
    5. Pulled the OBDII connector down and tested the 4 (yes a total of 4) pins : pin 2 to pin 5 -check, pin 4 -- grounded check, pin 5 -- grounded check, pin 16 - power - 12 volts - check

    So there is something shorting on the serial 2 data line.
    Now my plan of attack is to remove the driver side seat so I can lay on my back and get to the white splice pack under the dash.
    Remove the splice pack covering and prob for continuity on each pin/line combination until I can find which sensor or module is acting up.

    Fortunately, I have an MRI tomorrow and its going to be nearly 90 so I doubt I will work on the boat anchor until Friday.

    JW
     
  10. Aspen500

    Aspen500 Well-Known Member

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    Something we've run into a couple times at work on Suburban's when the network goes down is the suspension control module shorting due to internal corrosion. In Texas, this may not be a problem though. The module is under the truck, above the spare tire area. Prime location for water, salt and other assorted crap. That's assuming you have load leveling suspension (air shocks and compressor in the back). Would be a good place to check first. When it shorts the network, the engine dies and won't crank, the instruments either don't work or go nuts, doors may lock and unlock randomly, etc., or everything will just be dead. The corrosion will be inside the module so it may look fine externally. If you unplug it, that should let the network come back on-line IF it's the fault. IIRC, with it unplugged everything will work again except there will be a "check suspension" message and/or warning light on in the cluster.
     
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  11. Justwondering

    Justwondering Well-Known Member

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    good idea, but mine has no fancy load leveling suspension.

    did get the MRI done though.
    no results for 2 days which of course means it will be Monday. :)

    JW
     
  12. Aspen500

    Aspen500 Well-Known Member

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    Well,,,,,,,,,,,,it was worth a shot! lol You must have one of the odd ones.:eek: I can't recall ever seeing a Suburban (2000 and up anyways) that didn't have load leveling shocks out back. How many of those still work? Not manyo_O
     
  13. Justwondering

    Justwondering Well-Known Member

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    Unplugged the PCM (both banks) after letting the battery sit with the negative lead off for about 6 hours.
    Waited about 10 minutes and then plugged the PCM back in.
    Tried the relearn process -- did not work.

    Radio plays, wipers work, running lights work, rechecked all fuses to be sure nothing popped.

    looks like tomorrow is remove the driver seat and the passenger rear seat.
    unplug splice pack 2 from the rear seat.
    remove the bus bar from splice pack 1 under the dash
    prob the wire leads one by one to see if there is a dead module somewhere in the data link.

    I'm thinking if that doesn't give me any more information.
    I might as well pull the pcm and the bcm and have them reflashed -- then try again.

    Meanwhile, when it gets hot tomorrow afternoon, I'll continue the search for a key fob that might match the suburban.

    Cheers,
    JW
     
  14. Justwondering

    Justwondering Well-Known Member

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    Exactly why is there a special E-socket for the seat bolts that go through the floor?
    My Mopar didn't have that. Just bolts.

    Now, I have to make a trip or order online to get a special e-socket to get the dang seat off so I can get enough room to comfortably prob the first splice pack
    OR to remove the second splice pack.

    I wish I had looked at this earlier today before I made what I thought was my last trip to town for a few days.

    I did remove the BMC again and look inside it this time -- no fluid, no burn spots, no swelled capacitors ... all looks good.

    JW
     
  15. Aspen500

    Aspen500 Well-Known Member

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    Oh yes, those seat bolts! IIRC, there's two different sizes. I believe the front bolts are E20 and the rear of the track are E18. Would have been too easy to make all 4 the same size I guess.

    Wish the Enterprise was near, I'd beam you my E-socket set to use.:cool:
     
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  16. Justwondering

    Justwondering Well-Known Member

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    I went with plan B.
    I figured out a way to lay on a cushion, on a bench, next to the vehicle with the door open.

    Pulled the bus bar from the splice adapter.
    With Key On Engine Off (KOEO), I used my voltmeter set at 12 volts and put the red lead on the power wire (brown) then sequentially tested each of the other connectors in the splice pack.

    My results were:
    top row
    1 - Brown : .55 (grounded to the frame and red probe on the brown wire)
    2 - White : .21 (red probe on brown wire, black probe on the white wire)
    3 - purple : .53
    4 - lt blue : .54
    5 - dk green : -0.03 (this seemed like the problem child to me)
    6 - Pink & Orange wires : .54

    bottom row
    7 - gray : .12
    8 - dk blue : .27
    9 - empty
    10 - empty
    11 - tan : .01
    12 - lt green : 0.0

    Popped over to the autozone site to join so I could look at wiring diagrams for a 2003 suburban.
    Started at the top under the electrical items and saw this (I added the blue arrows):
    Inked2003 suburban right front door electrical.gif

    I want to understand how to interpret this drawing.
    Is this telling me that at the front passenger door (assuming I remove the inner panel so I can get to the wires) that I should find a dark green wire.

    When I find the dark green wire, if I use my voltmeter set to 12 volts
    place my black probe on the chassis frame for ground,
    place my red probe on the end of the dark green wire,
    KOEO,
    that I should see .35 on my voltmeter?

    JW
     
  17. Justwondering

    Justwondering Well-Known Member

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    FYI .. I'm going through these unnatural acts because
    1. I don't own a Tech 2 scanner or equivalent
    2. I'm not sure I can get the surburban onto a trailer and down to the mechanic without major help from the neighbor. Husband definitely can't help right now. His heart is struggling with all the humidity and breathing is difficult.

    So I'm trying a low tech process and a bit of deductive reasoning.

    IF the dark green wire is the problem at the splice pack, then I should be able to find a module or connector that I can unplug so it takes the problem component off the serial 2 network. With the offending component offline, I should get back my OBDII communication.

    Thanks my working hypothesis at this point.

    JW
     
  18. Mikes5thAve

    Mikes5thAve Active Member

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    .35 is probably wire size.
    You have to be careful checking it like you're doing. Some of the signals that the modules are working with the voltage or resistance it's looking for is so low you can fry the module with the meter.

    A defective door switch or wiring shouldn't be causing a no start problem.
     
  19. Justwondering

    Justwondering Well-Known Member

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    thanks Mike.
    So the diagram is probably just telling me what color wire is going where, not necessarily what the voltage or resistance should be.

    Its looking like the middle plug on the BCM has a short in the dark green wire.
    I'm printing documents to figure out every place the dark green wire goes ASSUMING they were consistent in using the green wire as per the documentation.

    Then I plan to remove the component that use the dark green wire.
    At that point, I can check continuity on the green wire and that will either support my 'shorted green wire' hypothesis OR it wont support the idea.

    I've got another 24 hours before it rains again and I'll have to stop futzing with it for a while

    JW
     
  20. Mikes5thAve

    Mikes5thAve Active Member

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    No, the wiring diagrams just shows the wiring.

    dark green says it's for right front door switch, if it knows when the door is opened and closed the wiring would be OK.

    BUT the dark green wire you've arrowed looks like its between the door module door switches, not directly to the BCM.

    You might want to try getting an alldata account and see what it says about this problem. There should be some sort of trouble shooting chart to narrow down what to check for the problem. It's cheaper then paying $200 for the service manuals on ebay only find out you need the dealer scan tool to do anything.
     
    Last edited: Mar 28, 2020 at 8:25 PM