Bought, wrecked, rebuilding a 2009 LMM

Ron Nielson

Active member
Oct 11, 2009
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Berryton, KS
What I haven't found, is how does the ECM get the request to crank?
Where/how does the switch send the request? Is it a momentary signal to the BCM then sent via data cables/can bus? Or wire straight to the ECM?
The BCM start messages via CanBus, not straight wire to the ECM, ECM checks to see if it's ok to run the starter (not in gear, etc). I have no idea within the BCM what happens but as long as you hold the key in START, the starter will run. To me that says it's continuous
 

malibu795

misspeelleerr
Apr 28, 2007
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The BCM start messages via CanBus, not straight wire to the ECM, ECM checks to see if it's ok to run the starter (not in gear, etc). I have no idea within the BCM what happens but as long as you hold the key in START, the starter will run. To me that says it's continuous
Im basically trying to use the start circuit to figure out if the BCM is bad or not.

I found the #1020 circuit shortly before bed last night. Hopefully test it tonight
 

malibu795

misspeelleerr
Apr 28, 2007
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@Ron Nielson that's a much nicer picture of what I grossly pieced together. Going to verify the ignition switch is working and verify the BCM is being told something via the switch.

I have found that the RPM/MPH/FL/EOP/TFT/ECT info along with TH, CC all run through the BCM and none of that stuff works. And can't read codes
 
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malibu795

misspeelleerr
Apr 28, 2007
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Why is Garret "running"? Is he personally delivering it?
Having this service provided
 

1FastBrick

Well-known member
Dec 1, 2016
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Having this service provided
Oh.... hit the R instead of the T. oppsie...:LOL:

Make's a big differences... I was picturing Forrest Gump running with a BCM all the way to your house. :ROFLMAO: Run Forest, Run!!!!
 

malibu795

misspeelleerr
Apr 28, 2007
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Or maybe it was the Spell Check. Either way Forest is on his way in my mind...:ROFLMAO:
Spell check worked just fine, gramar kinda...


Burb, I bought new cam sensor, pig tail and intake gaskes, and problem went away.... So motivation to dig into it has diminished ??‍♂️

Also trying to save for a set of these for my wagon..
 

malibu795

misspeelleerr
Apr 28, 2007
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Nope, also been trying to help a guy do a engine swap on a 86 olds Cutlass 442 about 45 minutes away.. his eyes are bigger than his knowledge or pocket book is but has a willingness to learn
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Nope, also been trying to help a guy do a engine swap on a 86 olds Cutlass 442 about 45 minutes away.. his eyes are bigger than his knowledge or pocket book is but has a willingness to learn
350? 455? Please, dear god, not another LS swap.....
 

malibu795

misspeelleerr
Apr 28, 2007
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Got the tracking number, BCM "should" be here by close of business Friday..
Also called dealer about new ignition cylinder and key. Current setup generally has to be jiggled to cycle from OFF. The doors, for the most part are fine.
I'm looking at ~250-300 for ignition cylinder, it being built and a fresh key cut to match.. add another 150 per door.... that's a project that can wait a bit
 

JoshH

Daggum farm truck
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Feb 14, 2007
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Also called dealer about new ignition cylinder and key. Current setup generally has to be jiggled to cycle from OFF. The doors, for the most part are fine.
I'm looking at ~250-300 for ignition cylinder, it being built and a fresh key cut to match.. add another 150 per door.... that's a project that can wait a bit
You probably just need a new key. You should be able to get a dealer to cut a new one from the key code that they can find using the VIN as long as you can provide proof of ownership.