B3: Check For O2 Sensor Heater Continuity

Ignition switch to position 0
Disconnect EM021
Bracket on top of gearbox or Bulkhead rear of engine
With EM021 disconnected, measure the resistance between EM021/001 and EM021/002.

Is the resistance between 4 and 10 ohms?

Yes
GO to B4, B4: Check For O2 Sensor Failure

No
Renew O2 sensor, reconnect plug(s).
GO to B8, B8: Stop