A12: Check For Heated O2 Sensor Continuity

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

Is the resistance < 0.5 Ohms?

Yes
Go to A13 A13: Heated O2 Sensor Screen Ground Continuity

No
Inspect connectors EM012, & EM021 for corrosion, damaged / pushed back pins or repair the harness; reconnect plug(s).
Go to A18 A18: End