With GST
- Start engine and warm it up to normal operating temperature.
- Set voltmeter probes between ECM terminal 114 [HO2S1(B1) signal] 115 [HO2S1 (B2) signal] and ground.
- 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.
- If NG, go to DIAGNOSTIC PROCEDURE .