2006 Cadillac SRX codes received U1000 & P0446

Question

Had a new motor put in March 2015... why is this happening - check engine light it on also

Answer 1

P0446 Evap vent system perfromance

U1000 Class 2 communication malfunction

U1000 is a class 2 communication , depending on which module is not communicating a U1000 set, Some of the module that you have are the audio,driver door module,electronic brake control module, electronic suspension control module,HVAC module,instrument cluster module, ECM , whats listed is just a few module, To find which module is not communication it would be the module that does not store a code. As for a P0446 this is for the EVAP system  with the vent control system, start by checking the fuel cap, poor sealing of the fuel cap can cause this code to set, other times when it comes to this code the FTP( fuel tank pressure) sensor should be suspected. what happens the FTP sensor does not report the correct pressure/vacuum in the fuel tank .