B12: Signal Ground 2 Continuity

With EM010 and EM014 disconnected, measure the resistance between EM014/004 and chassis ground EM008L.

Is the resistance < 0.5 ohms?

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

No
Inspect connector EM014 for corrosion, damage, or pushed back pins.
Inspect earthing stud EM008L for corrosion.
Inspect harness, splice EMS36.
Repair as required and reconnect plug(s).
GO to B13, B13: Check For Heated O2 Sensor Continuity