Oxygen Sensor: Testing and Inspection

Fig. 41 Check Connector Test Harness:

1. Install check connector test harness.
2. Raise engine temperature to operating temperature.
3. Hold engine speed at 3000 RPM for two minutes.
4. Connect check connector test harness brown terminal (11) with black ground terminal.
5. Connect a volt/ohmmeter between green terminal (36) and engine ground, Fig. 41.
6. Hold engine speed at 1500 RPM. Ensure reading of volt/ohmmeter changes eight times or more in ten seconds.
7. If reading changes less than eight times, proceed as follows:
a. Disconnect brown and black terminal on check connector test harness.
b. Hold engine speed at 3000 RPM for two minutes.
c. Connect the brown and black terminals together and hold engine speed at 2500 RPM.
d. Ensure reading of volt/ohmmeter changes eight times or more in ten seconds.
e. If reading changes less than eight times, replace oxygen sensor.
8. If reading does not change at all, proceed as follows:
a. With engine at operating speed, hold engine speed at 3000 RPM.
b. Reduce speed and hold at 1500 RPM.
c. Connect brown and black terminals on the check connector test harness together.
d. Measure voltage between terminal 36 on the check connector test harness.
e. If voltage is 5 volts, air to fuel ratio is too rich.
f. If voltage is 0 volts, air to fuel ratio is too lean.
g. Correct fuel ratio and repeat test procedure.
9. Perform Oxygen Sensor circuit test. (1.0L Engine)

Fig. 46 ECU System Diagnosis, Oxygen Sensor Check:

9. Perform Oxygen Sensor circuit test. (1.3L Engine)

Fig. 58 ECU System Diagnosis, Oxygen Sensor Check: