No crank/start/anything condition with radio also in locked mode.

Discussion in 'Engine & Drivetrain' started by Alberta Tahoe, Aug 6, 2017.

  1. Alberta Tahoe

    Alberta Tahoe Full Access Member

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    I've been trying to remedy a problem with the issues listed in these two threads.

    http://www.tahoeyukonforum.com/threads/electrical-issue-is-expanding.93566/

    and here:

    http://www.tahoeyukonforum.com/threads/intense-electrical-issue.92892/page-2#post-1113447

    Short story now is that there is a no start or crank condition. Despite replacing the ignition switch (or operating it manually when removed from the lock cylinder for that matter) turning it to the start position does absolutely nothing. The gauges don't even drop to zero as is usually the case. Removing the key will not turn off the gauges or indicating lights either. That is accomplished by disconnecting the battery.
    What's more, what appears to be normal dash function (after disconnecting and reconnecting the battery), will allow the radio to be turned on. However, that will only last for a minute (or less) before it shuts down and displays "LOCKED".
    In all of my fiddling is it possible that I've activated the theft deterrent system?
    If so, what is the remedy? HP Tuners or similar software to access the PCM?
     
  2. Alberta Tahoe

    Alberta Tahoe Full Access Member

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    Nobody?
    OK. Here's another couple of questions. What would cause a vehicle (in this case a 2006 Tahoe) to go into an anti-theft mode? And if a vehicle is in the anti-theft mode, what has to be done to undo it?
     
  3. Jarrid

    Jarrid TYF Newbie

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    Well idk if this helps but my radio locked up and I ended up yanking the little black anti theft connector from the circuit board in the radio after that the radio was good
     
  4. Alberta Tahoe

    Alberta Tahoe Full Access Member

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    Thanks for that.
    Now the questions are:
    Why did the radio lock up?
    And why do I have a no crank condition now?
    How does a vehicle behave when the anti-theft has been activated?
     
  5. retiredsparky

    retiredsparky Full Access Member

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    Since you aren't getting any feedback, you are on your own. Take it to a shop that has the tool (tech tool?)to read the codes and troubleshoot the ECM and BCM. I believe the gauge cluster has the timers built in to control power to the gauges, etc.

    Have you checked the basics=good battery voltage, no corroded terminals?
    Larry
     
  6. Alberta Tahoe

    Alberta Tahoe Full Access Member

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    I think I'm at that point. When I used my cheap code reader, no trouble codes came up despite the check engine having been on. That was at a time when the vehicle actually ran. Having removed and replaced the battery several times, any code that existed wouldn't be picked up by reader anyway. Now the GM Tech 2 scanner is what I need. I may just have it towed to the dealer and have them hook it up and give my print out (if that's possible).
    As for the basics, yes, I've gone over just about every connection under the hood at this point. Nothing unusual. That said, I firmly believe that this whole litany of trouble started with a poor connection somewhere.
    I'm well past that now. Something has gone haywire what with having re and re'd the BCM and PCM. Plus a new ignition switch.
    I'm going to take one last stab at it this week and then seek professional assistance I guess.
     
  7. M1Gunner

    M1Gunner Full Access Member

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    If the vehicles anti-theft was enabled then you would a CRANKING but no-start condition. On the initial start up after it is enable the the engine will actually start for a sec or two and then shut-off because the anti-theft wil shut down the fuel injectors on our trucks. Which would still allow the vehicle to crank over and have spark but no fuel delivery.
     
  8. M1Gunner

    M1Gunner Full Access Member

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    One more time, if you don't mind, describe what makes happening. Start from the beginning. When you open the door do lights come on? Does the vehicle chime when you put the key in the ignition? What happens/activates when you turn the key to the on position? Etc. try not to leave out any details.

    Here's a diagram for the starting system also if you don't have it.

    IMG_3743.PNG
     
  9. Alberta Tahoe

    Alberta Tahoe Full Access Member

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    First off, thanks for the interest. I've several threads about what's been happening but I'll try to provide a summary here.
    At first, the vehicle would momentarily shut down while driving over bumps. Cruise would kick off, door locks activated/deactivated, instrumentation drops to zero. Then just as quickly, everything would be restored and the vehicle drives as normal. This was going on for thousands of miles with not really much change one way or the other.
    I did a check of all of the basic items. Replaced the battery. Checked all of the power cables that I was able to check. Replaced a ground wire from the firewall to the block.
    No change whatsoever.
    Then the truck was parked for two weeks. When I returned, all electrics were completely dead. Absolutely nothing came on. Figured I had left the interior light on while I was away. A boost did nothing. A battery replacement did nothing.
    Now on to where I'm at presently. And this is where it gets interesting.
    With a fresh battery, getting into the truck is as normal. Inserting the key activates the "door is open" chime. Turning to "on", the instruments and warning lights come to life. Turning to the "crank" position does nothing. And by nothing I mean there is no change whatsoever. The instruments stay as they were in the on position rather than momentarily going to zero as they would normally. In addition to that, removing the key does not turn off the instrument panel entirely. The warning lights remain on although they are at a reduced intensity (as in not fully bright). To deactivate the gauges: the battery has to be disconnected or the PCM fuse pulled or there is a connector to a module on the firewall (adjacent to the master cylinder) that when removed will cause an audible "click" in or around the throttle body. After any of those operations are performed, all gauges reset to rest position and I can repeat the process.
    For the record. The electrical portion of the ignition switch has been replaced. In as far as I can tell, it's functionality is as it was before replacement. I've removed and reinstalled the PCM and BCM.
    Other than that, I've done nothing.
    I'll answer any and all questions if you have any.
     
  10. Jarrid

    Jarrid TYF Newbie

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    bump to get this problem solved having my own problems with my own hoe about to set it on fire and watch it burn either way good luck!!!!!
     

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