got my rebuild started for the first time today

. but 2 current codes im working on:
05 - Knock Sensor
25 - Solenoid (Pressure Regulator Control)
had a 16- EGR Valve that i already figured out (loose connector)
any common wiring problem that can contribute to both 05 and 25? i already reset the ECU to see if they would go away on their own but no. checked the connection on the knock sensor.. looks good. checking solenoid will have to wait until tomorrow morning.
also, i have a exhaust leak from around the turbos/dp that i had before the rebuild.. and has not gone away. not sure where it could b from.