Oxygen Sensor: Testing and Inspection

1. For 1981-82 3T-C engine, disconnect vacuum hose between vacuum control valve for evaporative emission system and vacuum connector at connector and plug vacuum connector.

2. For 1981 22R and 1981-82 3T-C engines equipped with high altitude control system, disconnect vacuum hose between high altitude control valve and check valve at check valve and plug check valve.

Fig.86 - Testing Oxygen Sensor Circut:

3. Connect voltmeter to service connector, Fig. 86.

4. Run engine at 2500 RPM for approximately 90 seconds, then, maintaining engine speed, check that needle of voltmeter fluctuates at least 8 times in 10 seconds within zero to 7 volts range.

5. Reconnect vacuum hoses and air hoses to proper locations.

6. If test results are not as described, check other components, connections, and wiring of air injection system. If no problem is found, replace oxygen sensor.