A2: Check O2 Sensor Heater Continuity

Ignition switch to position O
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 A3 A3: Check For O2 Sensor Failure
No
Renew O2 sensor; reconnect plug(s)
GO to A6 A6: Stop