Tester Display (Sensor)

Voltage Variations

Proceed To

AFS B1 S1 (A/F)

Alternates between more and less than 3.3 V


Remains at more than 3.3 V


Remains at less than 3.3 V

A normal HO2 sensor voltage (O2S B1 S2) reacts in accordance with increases and decreases in fuel injection volumes. When the A/F sensor voltage remains at either less or more than 3.3 V despite the HO2 sensor indicating a normal reaction, the A/F sensor is malfunctioning.

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