Download Use this procedure to check the overall function of the heated oxygen sensor 2 (rear) circuit. During this check, a 1st trip DTC might not be confirmed. WITH GST 1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes . 2. Stop vehicle with engine running. Zoom Sized for Print 3. Set voltmeter probes between ECM terminal 72 [HO2S2 (B1) signal] or 71 [HO2S2 (B2) signal] and engine ground. 4. Check the voltage when racing up to 4,000 rpm under no load at least 10 times. (Depress and release accelerator pedal as soon as possible.) The voltage should be above 0.56 V at least once during this procedure. If the voltage can be confirmed in step 4, step 5 is not necessary.