Overall Function Check

Use this procedure to check the overall function of the heated oxygen sensor 1 circuit. During this check, a 1st trip DTC might not be confirmed.

With GST 

1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 16 [HO2S1 (B1) signal] or 35 [HO2S1 (B2) signal] and ground. See Figure .
3. Check the following with engine speed held at 2,000 RPM constant under no load.
   • The voltage fluctuates between 0 to 0.3V and 0.6 to 1.0V more than 5 times within 10 seconds.
     1. 1 time: 0 - 0.3V --> 0.6 - 1.0V --> 0 - 0.3V 
     2. 2 times: 0 - 03V --> 0.6 - 1.0V --> 0 - 0.3V --> 0.6 - 1.0V --> 0 - 0.3V 
4. If NG, go to DIAGNOSTIC PROCEDURE  .