Hyundai 39210-23750 Sensor Assembly-Oxygen

You can Select Your Vehicle to check if 39210-23750 fits your vehicle.

All vehicles covered are equipped with an upstream and a downstream Heated Oxygen Sensor (HO2S). The upstream HO2S is located ahead of the catalytic converter on models from 1996 to 2000, while on 2001 and later models, it is found in the exhaust manifold; the downstream HO2S is positioned behind the converter. The upstream HO2S monitors the oxygen content in the exhaust gas stream, producing a voltage output ranging from 100 millivolts for a lean mixture to 800 millivolts for a rich mixture, which the PCM uses to adjust the air/fuel mixture for optimal emissions. The HO2S must reach approximately 600 degrees F to function correctly, and during warm-up, the PCM operates in open loop mode. Proper operation of the oxygen sensor depends on clean electrical connections, adequate air supply, correct operating temperature, and the use of unleaded fuel. The downstream HO2S functions similarly but is used by the PCM to monitor catalytic converter efficiency. Caution is advised as the HO2S is sensitive to circuit loads; testing should be done with a digital voltmeter, and care should be taken to avoid damaging the sensor. Voltage readings from the upstream HO2S should fluctuate between 100 and 800 millivolts, while the downstream HO2S should remain stable. Battery voltage and ground circuits should be checked, and the oxygen sensor heater should be tested for an open circuit. If issues persist, the wiring harness and connectors should be inspected. For replacement, the exhaust pipe should be warmed to ease removal, and care should be taken to avoid damaging the HO2S or its connectors. Anti-seize compound should be applied to the threads before installation, and the sensor should be tightened to the specified torque before reconnecting the electrical connector and lowering the vehicle.