A3: Check For O2 Sensor Failure

Run the engine for a period to warm the sensor and then maintain a steady speed of approximately 2500 rpm.
Disconnect EM021

Bracket on top of gearbox or Bulkhead rear of engine

With EM021 disconnected, measure the voltage between EM021/003 and EM021/004.

- Is the voltage between 600mV and 1.0 Volt?
Yes
GO to A4 A4: Check For O2 Sensor Failure
No
Renew O2 sensor; reconnect plug(s)
GO to A6 A6: Stop