2. Check that the circuit between terminal 1 and terminal 3 of the oxygen sensor connector is closed (resistance between terminals is 11-18 Ohms at 20°C).
3. If the circuit is broken, replace the oxygen sensor.
Note: If the MUT-III does not show nominal values, despite the fact that previous resistance and wiring checks showed full serviceability, replace the oxygen sensor. For removal and installation of the oxygen sensor, see Section "Exhaust system downpipe and main muffler".
4. Warm up the engine to a coolant temperature of 80°C or higher.
5. Set the engine speed to 4500 rpm for 5 minutes.
6. Connect digital (electronic) voltmeter to terminals 2 and 4 of the sensor connector.
7. Periodically pressing the accelerator pedal, measure the output voltage of the oxygen sensor.
Good condition:
| Engine | Oxygen sensor output voltage | Note |
| When you press the accelerator pedal | 0.6-1.0 V | If you enrich the fuel-air mixture by periodically pressing the accelerator pedal, then a working oxygen sensor will output a voltage of 0.6-1.0 V. |
8. If the oxygen sensor is faulty, replace it.
Note: For removal and installation of the oxygen sensor, see Section "Exhaust system downpipe and main muffler".