The two tone color wired is staying grounded which is the green & white wired
The wire goes to pin 8 of the ECM and to the EVAP solenoid on one side and this side will ground the solenoid to control it. If the circuit is keeping the EVAP solenoid on all the time, then you need to disconnect the connector at the ECM and EVAP and see if it is still shorted to ground. If it is, then you need to trace the harness to see if it is chafed and grounded somewhere. If the wire is no longer grounded then you may have an ECM short.
Make sure you are using a digital multimeter to check for grounded circuit. You should also use a scanner to turn the EVAP solenoid on and off to see if the ECM is able to operate it.