lbz keyless entry

DAVe3283

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Sep 3, 2009
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You should be able to flash the ECU without a security learn l. If the ECU isn't flashing, there's possibly something on the bus that is interfering with the flash. Could explain what happened to the first BCM as well.

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Yngdmax92

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Sep 26, 2013
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been a mechanic for 13 years now. My biggest rule was always not to over think things. This truck rolled in the shop perfectly happy and running fine, just installed injectors in it and flashed a fresh file in it a couple weeks ago via efi live. If all i did was try to flash a bcm file in it, and im assuming it locked up the bcm and wont stay running. i am going to stick to my guns and say there is still something wrong and the modules arent happy. Whether its security related, or the bcm truly does need to be there to talk with the ecm/tcm. I think it would be a bad idea to try and start digging apart the electronics looking for something that is not there.

update, had a older school tech look at it. he truly believes that the new system (mdi 2) talks to fast to make this possible to program because the gmt 800 trucks were designed to be programmed with a pass through programming. So at this time, he is going to write up a repair order on it and get in touch with technical assistance. See what they have to say about it.
 

DAVe3283

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Right, but if you used to be able to flash the ECU with EFILive, and now can't, something changed. I don't think the security learn needs done before an ECU flash, but I don't know for sure.

Curious how this turns out.

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Yngdmax92

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well, dont forget, they did flash the ecm back to factory file. i am now wondering if because i dont have the base dsp5 file in it from mark danville, i only have a updated dsp5 file from him. so that could be it. i should probably message him and ask him for the whole thing. its only 1mb the, updated file is.
 

Yngdmax92

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Dave was 100 percent right about the damn radio.... I did unplug it, but I did just that. I unplugged the radio. Today when I was messing around with it after work, I unplugged the radio again and tried to isolate the bcm 100 percent, even unplugged aftermarket trailer brake. What I noticed was when I went to go turn my damn key on was the door chime was running, which it. Shouldn't be doing with the radio on. So, I looked back in further and there is a customer harness that was installed(crutchfield brand). It must be it was by passing some securities or some or keep a signal going for the doors to chime. I don't really know, but I unplugged the piggy back harness from the gm harness and out went the door chime. I new I was good to go, it took a bcm flash. Flashed the keyless entry into it and put the whole truck back together, flashed in the good old spicy Danville tunes and were off. Drove my butt rght to the junk yard and started pulling apart passenger door modules till I found a 03-07 loaded truck ( figured loaded trucks usually have rke). Found a pdm with rfs it says on it. Slapped it in my truck and wella. Got me some damn key less entry boys!

Thanks again fellas!
 

DAVe3283

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Sep 3, 2009
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Glad you got it all going!

My Suburban has an aftermarket radio module, and I have to pull the dang radio fuse to flash anything successfully.

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Yngdmax92

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Glad you got it all going!

My Suburban has an aftermarket radio module, and I have to pull the dang radio fuse to flash anything successfully.

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That's all you have to do is pull the damn radio fuse?? Jeez! I never tried that, I pulled dash apart and pulled radio and then proceeded to flash.
 

Yngdmax92

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Also boys! Every time I get out of my truck I always look back and hit that button smiling watching the lights flash and lock and even better when I return to the vehicle. The way I have my boost auto mirrors wired in, the reverse back up lights kick on when I unlock acting like entrance lighting.... Who needs a 2022 truck when you got these options! Haha
 
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DAVe3283

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Sep 3, 2009
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That's all you have to do is pull the damn radio fuse?? Jeez! I never tried that, I pulled dash apart and pulled radio and then proceeded to flash.
Typically yes, you just need to pull the radio fuse. Sorry, should've mentioned that.

If you need to flash your truck again, try just pulling the radio fuse (it's in the under hood fuse box) and I bet it works.

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Yngdmax92

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Yea I mean I did that all the time with my lb7, but that was for ecm flashes via efi live and not causing any interrupting with power. Hmmmm, not I'm really interested. Will report back on this as well.
 

Cougar281

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Sep 11, 2006
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Yea I mean I did that all the time with my lb7, but that was for ecm flashes via efi live and not causing any interrupting with power. Hmmmm, not I'm really interested. Will report back on this as well.
The reason for it was sometimes devices like that aftermarket module don't listen and shut up when a tool sends out the message on the byscfor all modules to 'stop talking', so they keep chattering, which can/will cause issues flashing. This would apply to flashing anything on the data bus. The radio fuse being pulled doesn't apply to flashing the LBZs because the ECM and TCM are flashed using the HS GMLAN bus, everything else is class 2. FWIW, I never pulled any fuses flashing my truck when it was still a LLY and never had any issues.

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Yngdmax92

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Where were you a couple days ago???? And yes, tis2 kept saying data 2 error until I pulled that damn harness. Pulled it, life was good.