H3: Check For O2 Sensor Failure

Ignition switch to position 0
Disconnect EM024
Bracket on top of gearbox or Bulkhead rear of engine
Run the engine for a period to warm the sensor and then maintain a steady speed of approximately 2500 rpm.
With EM024 disconnected, measure the voltage between EM024/001 and EM024/002.

Is the voltage between 600mV and 1.0 Volt?

Yes
GO to H4, H4: Check For O2 Sensor Failure

No
Renew O2 sensor. Reconnect plug(s).
GO to H7, H7: Stop