Honda 8-25312-200-0 Sensor, Heated Oxygen (Pos)

The oxygen sensor, located in the exhaust manifold, measures the residual oxygen content of the exhaust gas stream and produces a voltage output which varies from 0.1-volt (high oxygen, lean mixture) to 0.9- volts (low oxygen, rich mixture). The PCM alters the air/fuel mixture ratio by controlling the pulse width (open time) of the fuel injector(s). To test the oxygen sensor, use a digital voltmeter to back-probe the connector and measure the voltage output the sensor produces as it goes from cold to fully warm. If the oxygen sensor fails any of these tests, replace it with a new part. When servicing the oxygen sensor, take special precautions such as not removing the pigtail or electrical connector, keeping grease, dirt and other contaminants away from the electrical connector and the louvered end of the sensor, not using cleaning solvents of any kind on the oxygen sensor, not dropping or roughly handling the sensor, and installing the silicone boot in the correct position. To replace the oxygen sensor, disconnect the cable from the negative terminal of the battery, raise the vehicle and place it securely on jackstands, carefully disconnect the electrical connector from the sensor, carefully unscrew the sensor from the exhaust manifold, install the sensor and tighten it securely, reconnect the electrical connector of the pigtail lead to the main engine wiring harness, lower the vehicle and reconnect the cable to the negative terminal of the battery.