O2 Sensor Analysis Calculator

Analyze oxygen sensor voltage output to determine air-fuel ratio, sensor health, and switching characteristics.

Input Parameters

Results

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Est. Air-Fuel Ratio
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Lambda Value
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Sensor Health
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Cross Counts/min
Note: Narrowband O2 sensors switch around 0.45V (stoich). A healthy sensor switches 1-3 times per second. Replace if amplitude drops below 0.3V.

Reference

Lambda ≈ 1.0 + (0.45 − V_sensor) × 0.5 AFR = Lambda × 14.7 (stoichiometric) Cross Counts/min = Switch Rate × 60 Health: Amplitude ≥ 0.6V and Rate ≥ 1.5 Hz = Good Narrowband O2: 0.1V (lean) to 0.9V (rich)