H3: Check For O2 Sensor Failure

Run the engine for a period to warm the sensor & then maintain a steady speed of approximately 2500 rpm

With EM024 disconnected. measure the voltage between EM024/001 & EM024/002

Is the voltage between 600mV & 1.0 Volt?

Yes
Go to H4

No
Renew O2 sensor; reconnect plug(s)
Go to H7