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] 35 [HO2S1 (B2) signal] and ground. See Figure .
3. Check one of the following with engine speed held at 2,000 RPM constant under no load.
   • The maximum voltage is below 0.8V at least 1 time.
   • The minimum voltage is below 0.35V at least 1 time.
4. If NG, go to DIAGNOSTIC PROCEDURE  .