A7: Heated O2 Sensor Short Circuit to Ground

With EM021 disconnected measure the insulation resistance between sensor pin 001 & sensor body
Repeat for pin 003 & sensor body

Is the resistance > 10 M Ohms?

Yes
Go to A9 A9: Signal Ground 1 Continuity

No
Renew the O2 sensor & reconnect plug(s)
Go to A8 A8: Stop