No crank no start, no ground to 3 fuses?

2019 CHEVROLET SILVERADO
74,000 MILES • 6.2L • V8 • 4WD • AUTOMATIC
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DAVO23
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Hello to all! I'm looking for help/ good wiring diagram for my truck. It stalled at idle the other day and now no crank no start. The only code I get from scanning is U0100 (lost communication with ECM). I have three fuses under the hood with no solid ground reading. The three fuses are highlighted in pic below. A video testing for ground is in the video. Thanks to all for any advice or help at all!
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Mar 8, 2025 at 8:56 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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STRAILER
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I am not sure what you are talking about the fuse grounding? does the fuse have power on both sides? I saw the video, but I am not sure what the tester you are using is saying? Here are the fuse that run the PCM. Please go over them and get back to me.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the images (below).
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Mar 8, 2025 at 12:46 PM
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DAVO23
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Thank you, Ken for the wiring schematic. my scanner showed “ lost communication with ECM” after the stalling and no crank no start issue, I ordered a new ECM and plan to have it programmed after I receive and install it. I have key voltage to both sides of all fuses related. The crank/ start relay = good…. In the video I hook my test light to the battery positive and went through the fuses checking for ground… all were showing a ground in the fuse box. (steady light) except those three fuses which was a blinking light. I just thought that maybe I might have a bad ground somewhere in the system or broken wire.
Thank you, Ken.
Mar 8, 2025 at 1:50 PM
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STRAILER
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I see, I am wondering if the tester is seeing low voltage or no voltage? Can I ask which fuses gave you the bad test? It does sound like the PCM is bad, here is how to change it out. Once the electrical connectors are removed check them for corrosion. Check out the images (below). Let us know how it goes.
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Mar 10, 2025 at 8:49 AM
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STRAILER
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Also, you will need to remove the inner fender liner on the driver side front.
Mar 10, 2025 at 8:54 AM
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DAVO23
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The three fuses that weren't showing a solid ground were the highlighted ones in the attached photo. I have removed the PCM and installed a new one and am going to haul it to a dealership to have it programmed later this week. Hopefully this fixes the issue.

Thank you, Ken!
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Mar 10, 2025 at 10:22 AM
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STRAILER
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Yep, all we can do, please let me know what happens, have a good week ;)
Mar 11, 2025 at 9:55 AM