Stall at stop manual trans
Thread Starter
On The Tree
Joined: May 2023
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I am just about as lost as lost can get in understanding what the hell went wrong here. Got LS Droid to flash my Bin from before I wentr down this switching OS road and still got no starter and no fuel pump. Verified the wires are good. But if I am writting the software from before that ran the motor that must mean I have a hardware issue i.e. my PCU is toast. right?
Joined: Sep 2004
Posts: 3,148
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From: Downers Grove, IL
I guess the PCM could be toast, but I have yet to see one die like that. The only one I had killed was because I was changing the throttle area settings for the TAC and I don`t even think that was what killed it, I think it was going low on voltage during a clone flash.
What OS are you putting on it now that will not crank or fuel pump? The 2003 burban stock pcm.BIN?
What OS are you putting on it now that will not crank or fuel pump? The 2003 burban stock pcm.BIN?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
When you swapped OS did you do a write calibration and OS or a full clone write? If you did a read entire to start with you might wand to do a full clone write to see if that will restore functionality to the PCM using the 9405 OS.
Thread Starter
On The Tree
Joined: May 2023
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Yeah tried the last good running and then went to the original 2003 and not it wont let me do anything. Voltage 12.6 to 14.4 ground pin does nothing keeps saying it cant find an address to write kernal to
Thread Starter
On The Tree
Joined: May 2023
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Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Sounds like the PCM is hard bricked and would need a BDM to reflash it. I think the usb-BDM is around 80 bucks and being that you can get a used PCM for around 40 its probably not worth it. Easier to pick up a used PCM.
Thread Starter
On The Tree
Joined: May 2023
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Verdad Gallardo Joined: Sep 2004
Posts: 3,148
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From: Downers Grove, IL
https://new.pcmhacking.net/forums/viewtopic.php?t=6215 its a way to flash the chip if the chip is blank or has corrupted firmware.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I would pick up a 12586243 pcm that way it has 12v ac request and the 7603 OS already loaded. Swap to whatever engine and transmission segments you need and then you have the most common best supported operating system.
Thread Starter
On The Tree
Joined: May 2023
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picked up a 6243 out of a 4.3 van swapped segments and now I got fuel pump and starter kicks but only for a second then stops then goes again for a second and stops for a second and so on as long as I have key in start position. ne security light and I did remove Vats but is there another table somewhere that is cutting the starter every second? Something needs to be set at 10 not 1?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Attach a copy of your bin from it and I can take a look. The most complete XDF that I know of for that OS and really any OS is here https://pcmhacking.net/forums/viewtopic.php?t=8172 in post 1 as part of the zip file. I don`t know of a setting that would make the starter run for a second then stop, then keep running and stopping. Normally it would either work or not work.
Thread Starter
On The Tree
Joined: May 2023
Posts: 116
Likes: 4
picked up a 6243 out of a 4.3 van swapped segments and now I got fuel pump and starter kicks but only for a second then stops then goes again for a second and stops for a second and so on as long as I have key in start position. ne security light and I did remove Vats but is there another table somewhere that is cutting the starter every second? Something needs to be set at 10 not 1?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
There is a starter protection timer that shuts the starter down after 2 seconds if the PCM does not see the motor spinning. Do you have a scanner that will let you watch the RPM through the PCM as you crank the motor? I`m wondering if the PCM is not seeing a crankshaft position signal? That would explain why it cranks for 2 seconds then stops and repeats.
Found it the crank sensor was set to low resolution which would cause it to look for the wrong crank sensor signal. Try flashing the updated bin, you should only have to do a write parameters flash
Thread Starter
On The Tree
Joined: May 2023
Posts: 116
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There is a starter protection timer that shuts the starter down after 2 seconds if the PCM does not see the motor spinning. Do you have a scanner that will let you watch the RPM through the PCM as you crank the motor? I`m wondering if the PCM is not seeing a crankshaft position signal? That would explain why it cranks for 2 seconds then stops and repeats.
Found it the crank sensor was set to low resolution which would cause it to look for the wrong crank sensor signal. Try flashing the updated bin, you should only have to do a write parameters flash
Last edited by BReal408; Aug 18, 2025 at 10:07 PM.