2017 Silverado with P018B and P2635 Codes

[silverbirchmetallic]

I have a 2017 Silverado LS 4x4 Double Cab with 5.3L engine and 26k miles. The CEL lit up yesterday, and my Bluetooth scanner shows P018B and P2635 codes. I have monitored a few PIDs, and it appears that "Commanded fuel rail pressure B" is showing zero, although the "Fuel rail pressure B" is similar to "Fuel rail pressure A". I'd like to trace the command signal wire. This problem started right after I washed my truck at a touchless car wash that had an under carriage spray. Would anyone have a wiring diagram? I saw a link on this site for "http://www.gmupfitter.com/files/media/photo/578/Sierra_Silverado_Electrical_Body_Builders_Manual_Service_Manual_2015_en_US.pdf" , but it is no longer available. Open to any suggestions or ideas on what the problem is. The truck starts and runs like new with absolutely no issues. Thanks!

[BO TIE 1]

If it's running good maybe just try clearing the codes to see if they come back.

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[silveradosid]

send me your email and i will send you a copy of the pdf file

[silverbirchmetallic]

Thanks to silveradosid I was able to trace all the wiring. I couldn't find any broken wires, so I took it to the dealer. The dealer said everything "passed" and cleared the DTC. They test drove it and could not duplicate the failure. I'm not sure where to go from here. I have Googled similar problems that were due to a bad battery. My batt is reading 13.3V to 14.7V at the scanner. No idea if this is good or bad--batt is about 3.5 to 4 years old.