System Inspection

Heated Oxygen Sensor Heater Control System Inspection

With SST-Engine Signal Monitor.
1. Remove the ECM.




2. Connect the SSTs to the ECM.
3. Turn the ignition switch to ON and measure the voltage at ECM terminals 2A and 2B by using a voltmeter.

Specification: Below 1.0 V

4. Wait for 240 sec after engine start, then measure the voltage at ECM terminals 2A and 2B for 5 Sec.

Specification: Battery positive voltage

5. If not as specified, inspect following.
- ECM terminal 3B voltage (Mass air flow sensor)
- ECM terminal 4E, 4H voltage (Crankshaft position sensor)
- Heated oxygen sensor




With SST-New Generation Star Tester
1. Connect the SST to the data link connector-2.




2. Select the PID/DATA MONITOR AND RECORD function of the NGS.
3. Select "HO2SHR" and "HO2SHL" on the NGS display.
4. Verify that the NGS display shows "ON".
5. Wait for 240 sec after engine start, and verify that the NGS display is changed from ON to OFF for 5 sec.
6. If not as specified, inspect following:
- ECM terminal 3B voltage (Mass air flow sensor)
- ECM terminal 4E 4H voltage (Crankshaft position sensor)
- Heated oxygen sensor