You take it to a qualified repair shop , unless you know about GMLAN serial data networks . U codes are network communication codes , problem with a module not talking or the data bus has a problem . GMLAN is general motors version of C.A.N. - controller area network . Watch this video . https://www.youtube.com/watch?v=FqLDpHsxvf8
Invalid Data Received From Body Control Module
Body Control System Description and Operation
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The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. The BCM is wired to the high speed GMLAN serial data bus, low speed GMLAN serial data bus and Multiple LIN buses and acts as a gateway between them.
Power Mode Master
This vehicle body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determining the power mode that will be sent over the serial data circuits to the other modules that need this information; the PMM will activate relays and other direct outputs of the PMM as needed. Refer toPower Mode Description and Operation for a complete description of power mode functions.
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed bus and the GMLAN low speed bus for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
All communication between the BCM and a scan tool is on the high speed GMLAN serial data circuits. A lost communication DTC typically is set in modules other than the module with a communication failure.
The various body control module (BCM) input and output circuits are illustrated in the corresponding functional areas on the BCM electrical schematics. Refer to the Body Control System Schematics for more detailed information.
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Hi there's this website something like reliable-store and it is very amazing for manual for repairing servicing anything
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See below or get your local dealership to come out with their Scanner.
Tip & How-To about Cars & Trucks
Resetting a Vehicle Anti-Theft System
This is how you reset an anti theft system if you have the anti-theft light on, or your car is cranking, but you have no spark.
Doing a full reset of the anti-theft system.
Disconnect both battery leads for at least two hours.
Hold the negative and positive leads together for 5 minutes to fully discharge any power.
Put the key in the ignition, but not turned on. VERY IMPORTANT!
Connect the positive lead.
Connect the negative lead in one swift movement.
Wait 15 minutes for the system to fully reset.
Posted by Andrew... on Jan 14, 2018
You got another computer from where ? Was it programmed ? Anti-theft system key's programmed to new computer also ? Oil pressure switch is in the black connector - have seen bad oil pressure switch wick oil through the wire strands into the computer ,also bad coolant temp. sensor do the same thing .
There's a website that has all this information about all this and manuals everything totally free there are many actually but I personally like few
for now u can try reliable-store.... le t me know if u need help