B9: Heated O2 Sensor Short Circuit to Ground

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

- Is the resistance > 10 M ohms?
Yes
GO to B11 B11: Signal Ground/Continuity
No
Renew the O2 sensor and reconnect plug(s).
GO to B10 B10: Stop