Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77

    Anyone a GM tech?

    I need a BCM programed to my G8. I think that's what the issue is. I just messaged Lane.

    Here is the issue I'm having.

    Electrical gremlin popped up. I started the car after going into the store and it started normal and I started driving, but after 10 seconds I noticed the radio turned off, the gauges weren't working, contact dealer, tpms system fault, check abs messages also came on. After about 30 seconds of driving the messages went away and the gauges started to work again and drove normal. I had an issue last year that I couldn't chase down where I tried to unlock the car but it wouldn't unlock with the key fob, it also wouldn't start. That time I disconnected the battery let it sit and reconnected it. The car restarted but every message popped up on the screen. Back to this year, Went to start the car again a couple of days ago and the car won't crank over now. Same issue as last year.

    Checked the connectors at the pcm and they are tight. Changed the battery out and put a trickle charger in it, and now the car won't start. Abs fault, brake, tpms fault, contact dealer lights appear on the display. Atari gauges don't turn on. Hvac blows at full speed. Voltage shows normal, remaining fuel shows 0 gallons, coolant temp 0, engine oil life 0%, trans sump temp 0.
    Last edited by ChitownCraig; 04-21-2017 at 02:39 PM.
    09 SRM G8 GT

  2. #2
    Certified Dirty Old Man CMNTMXR57's Avatar
    Join Date
    Aug 2011
    Location
    Elgin/West Chicago
    Posts
    5,671
    Sounds like you have a power moding issue/intermittent connection issue somewhere in a circuit that is causing communication issues between modules on the GMLAN. This could be because your BCM is still in a sleep state.

    Reprograming the BCM wouldn't fix this. Once the BCM is programed, it should only have to be re-programed if you replace it. Your key wouldn't communicate with the car and the RCDLR and authenticate to it if there was something out of sync with the BCM.
    Last edited by CMNTMXR57; 04-22-2017 at 01:23 AM.


    Former GM Tech.

    Daily Drivers:
    2015 Chrysler Town & Country Limited Platinum (RT Platform) rocking with Stow-N-Go
    2007 Chrysler Town & Country Limited (RS Platform) rocking with Stow-N-Go
    1999 Chevrolet Suburban K1500 LT (GMT400)
    2009 Chevrolet Impala SS (LS4)

    Garage Queens:
    Main: 2004 Pontiac GTO
    Other: 2006 Cadillac STS-V

  3. #3
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77
    If I bring the car into a dealer would they be able to figure it out or are they going to be scratching their heads while I pull out my hair after looking at the bill?

    I added Atari gauges earlier last year. I had the three gauges added to them and had them programed to my Vin. Could that be causing the problem?

    The car also has a tune on it, but I didn't update/touch the ecm last year.
    09 SRM G8 GT

  4. #4
    Certified Dirty Old Man CMNTMXR57's Avatar
    Join Date
    Aug 2011
    Location
    Elgin/West Chicago
    Posts
    5,671
    1) They could. Chasing electrical gremlins are some of the hardest things to do. It's not like chasing a coolant or oil leak where you can see things. The problem is, these aren't normal GMNA vehicles, so they may not have had a lot of exposure to it's harnesses or electrical gremlins.

    2) Did you splice into a harness? Or was it plug-and-play? I seem to recall it was just P-n-P and then you have to have the VOIN# updated. If you spliced in, it is quite conceivable you could've chaffed something, moved something, shorted something, etc...

    3) Tune shouldn't have any impact.


    Former GM Tech.

    Daily Drivers:
    2015 Chrysler Town & Country Limited Platinum (RT Platform) rocking with Stow-N-Go
    2007 Chrysler Town & Country Limited (RS Platform) rocking with Stow-N-Go
    1999 Chevrolet Suburban K1500 LT (GMT400)
    2009 Chevrolet Impala SS (LS4)

    Garage Queens:
    Main: 2004 Pontiac GTO
    Other: 2006 Cadillac STS-V

  5. #5
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77
    I bought the correct harness. I think I read something from Chris white that he's seen them make the car do funny things if he doesn't program them and someone else does. I had someone else program them. Maybe I'll unplug them tomorrow, since they don't turn on with the car as of now for some reason.
    09 SRM G8 GT

  6. #6
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77
    So I unplugged the Atari gauges and then turned the key to the on position, same warnings in the dic, then about a minute later the radio turned on, the door chime came back, and the hvac stopped blowing full speed and started to work correctly, but a couple other messages appeared in the dic. Looks like it was reading correctly for about thirty seconds. Since the coolant temp, oil life and throttle position actual have read outs now instead of 0. But I think they are frozen. When I press the pedal it doesn't change the percentage. I get a throttle reading on my Aeroforce gauge when I move the throttle.

    I was about to start the car when the radio read "security lockout, data mismatch" something along those lines. The red light on the radio is flashing every other second.

    Turned off the key and back to on and now I'm back to the beginning with all of the dic warnings and the blower blowing at full blast.

    Took the key out and got out of the car. Now the dic, window switches, the tc and heated seat switches are staying lite up along with the parking lamp light indicator on the dash.
    Last edited by ChitownCraig; 04-23-2017 at 09:36 PM.
    09 SRM G8 GT

  7. #7
    Can't Type Shit Bohnman's Avatar
    Join Date
    Aug 2011
    Location
    Arlington Heights, IL
    Posts
    7,997
    Try unplugging the aeroforce gauges? I'm assuming you have the ones that are made for Can bus?
    2005 MBM LS2.5 490's rwhp/430's rwtq tuned by AMS assembled by Bohnman's Customs

    I'm the guy who does the lights, Radio's, Door Sills, Splitters, Mechanical work on the side
    http://www.bohnmancustoms.com

  8. #8
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77
    Quote Originally Posted by Bohnman View Post
    Try unplugging the aeroforce gauges? I'm assuming you have the ones that are made for Can bus?
    I unplugged them last night actually and disconnected the battery again. I'll see what happens when I reconnect the battery. I didn't have the Aeroforce gauge last year when this happened, but did have the Scangauge 2 connected.
    09 SRM G8 GT

  9. #9
    Certified Dirty Old Man CMNTMXR57's Avatar
    Join Date
    Aug 2011
    Location
    Elgin/West Chicago
    Posts
    5,671
    This all is kinda similar to plugging in a Tech 2 with a bad VCI module. It sends the vehicles' PCM into an epileptic seizure.

    Something in that interface isn't playing nice with the controller in the vehicle.


    Former GM Tech.

    Daily Drivers:
    2015 Chrysler Town & Country Limited Platinum (RT Platform) rocking with Stow-N-Go
    2007 Chrysler Town & Country Limited (RS Platform) rocking with Stow-N-Go
    1999 Chevrolet Suburban K1500 LT (GMT400)
    2009 Chevrolet Impala SS (LS4)

    Garage Queens:
    Main: 2004 Pontiac GTO
    Other: 2006 Cadillac STS-V

  10. #10
    Member
    Join Date
    Jun 2013
    Location
    Western Burbs
    Posts
    77
    Reconnected the battery, key fob unlocked the doors and the trunk button worked three times. Fourth time I pressed the unlock it didn't work. I open the drivers side door and notice the dic isn't lite up. Put the key in and turn it on and it reads all the error codes, brake, abs fault, tpms, Airbag fault, contact dealer, plus very low fuel on the dic with the blower going at full blast.

    Tried to start the car and it wouldn't start.

    Going into engineering mode shows 0 for everything. If I switch gears to anything, it still shows P in the dic.

    When I take the key out and close the door the lights in the switches don't stay on this time
    Last edited by ChitownCraig; 04-26-2017 at 07:04 PM.
    09 SRM G8 GT

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •