234-4087 Oxygen Sensor 4 Wires

Front oxygen narrowband sensor: only four wires, the pins are defined as two signal lines and two heating wires. When judging the narrow Oxygen Sensor, the red and black pens of the multimeter can be connected to the two signal lines, and its voltage value should ideally be about 0.45 V, above 0.45 is the mixture is too concentrated, below 0.45V is the mixture is too thin. And the voltage value should jump between 0.1V and 0.9V, if it is greater than 0.9V or less than 0.1V, the sensor will be damaged. In addition, the mass can be judged by measuring the resistance of the sensor heating wire, and the multimeter is set to ohms. The measured sensor resistance is typically about 10 ohms. If the measured resistance is significantly different from 10 ohms, the sensor is damaged.

Rear oxygen sensor: generally four-wire, basically the same as the front oxygen narrow frequency sensor, its pins are respectively defined as heating power line, heating duty cycle control line, rear oxygen signal line and ground wire. When determining whether the rear oxygen sensor is good, the voltage data stream of the rear oxygen sensor can be read using a diagnostic instrument. When the vehicle is idling, its voltage value is relatively stable, generally about 0.2V; when the throttle is inflated urgently, its voltage will rise rapidly, changing between 0.6V~0V and 0V. Of course, it can also be judged by measuring the resistance of the heating coil. If the resistance is significantly different from 10 ohms, it means that the sensor is damaged.