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I'm getting a u0100 after replacing the motor.i checked every fuse every relay and ground.to and from pcm and everything is seeing power that should and everything that should be grounded is showing ground I'm lost can some one please help thanks
It's important to know what module is setting the u1000 code, also which modules can communicate and which cannot.
I would probably start by checking the network resistance between pin 6 and pin 14 of the data link connector. Key off, (battery disconnected will definitely make sure there's no network activity to see the resistance measurement), with the network intact should report very close to 60ohms.
Just because I've had this problem with other GM products after dropping the engine, I'm going to hip shot a suggestion at you. Check that the EBCM (electronic brake control module or ABS module) connector is seated well.
Even if it looks okay, unlatch it and reconnect it and see if it restores communication to all the modules.
If the ECM and TCM are a combined controller, they might have one of the resistor. If they do, it may be open causing you to read 120 ohms instead of the 60 ohms. I don't know if there is a gateway or not. Check the Can Bus at the ECM and /or TCM to see if you still get the 120.
Did you unplug and carefully reconnect the the ABS module connector?
The way the network is layed out there will be no communication with anything further out on the network.
The resistance measurement favors an open in the in the network, and that's usually where it happens after dropping the drivetrain out of these things. Seen it probably 6 times...
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