- Start engine and warm it up to normal operating temperature.
- Set voltmeter probes between ECM terminal 114 [HO2S1 (B1) signal] or 115 [HO2S1 (B2) signal] and ground. See Figure.
- Check the following with engine speed held at 2,000 RPM constant under no load.
- The voltage does not remain in the range of 0.2 to 0.4V.
- If NG, go to Diagnostic Procedure .