B13: Check For Heated O2 Sensor Continuity

With EM012 and EM021 disconnected, measure the resistance between EM012/015 and EM021/003.

Is the resistance < 0.5 ohms?

Yes
GO to B14, B14: Heated O2 Sensor Screen Ground Continuity

No
Inspect harness/connectors EM012 and EM021 for corrosion, damaged/pushed back pins.
Repair as necessary and reconnect plug(s).
GO to B19, B19: End