P0444 - Evaporative Emission Control System Purge Control Valve Circuit Open

Ive had this P0444 code for over a year now and still cannot find any solutions for it.. It came coincidently the same day i got my cat-back exhaust installed
I've changed both evap canisters in the front and in the back underneath the car and the code still appears

If anyone has any advice or know what may be causing this then please chip in.. any help would be appreciated.. thanks!

 

Have you changed the evap solenoid valve? And double checked to make sure the wiring was not damaged when they installed the exhaust?