How to Measure a Four-Wire Oxygen Sensor?

[DelAlejandro]

The measurement method for a four-wire oxygen sensor is: 1. Start the engine; 2. Increase the throttle to reach 1500 RPM, then test the signal voltage of the oxygen sensor—the voltage should be between 0.1 and 0.9 volts for normal operation; 3. Measure the resistance between the two wires, which should be around 10 ohms. The function of the oxygen sensor is to convert oxygen content into a voltage signal and transmit it to the engine computer, enabling the engine to achieve closed-loop control targeting excess air. The working principle of the oxygen sensor is: using a ceramic sensing element to measure the oxygen potential in the car's exhaust pipe, calculating the corresponding oxygen concentration based on the chemical equilibrium principle, thereby monitoring and controlling the combustion air-fuel ratio to ensure product quality and compliance with exhaust emission standards.