How to Measure the Quality of an Oxygen Sensor?
2 Answers
Methods for measuring the quality of a car's oxygen sensor: According to the circuit diagram, disconnect the connection between the engine ECU and the oxygen sensor, then test the oxygen sensor. Measure the resistance of the heating elements on both sides of the main oxygen sensor, which should be between 5.1 to 6.3 ohms. Next, measure the voltage between the ECU terminals HTL and HTR to ground, which should be between 9 to 14V. The car's oxygen sensor is a critical sensing component in the fuel injection engine control system, playing a key role in controlling vehicle exhaust emissions, reducing environmental pollution, and improving the fuel combustion quality of the car engine. Oxygen sensors are installed on the engine's exhaust pipe.
You can tell a lot just by looking at the exhaust pipe. A while ago, my car's fuel consumption suddenly spiked, and there was a strong gasoline smell in the exhaust, so I suspected the oxygen sensor was faulty. This thing is plugged into the exhaust pipe and is specifically designed to 'smell' the exhaust. The simplest way to test it is to unplug the connector when the engine is cold and measure the resistance with a multimeter—the heating element's resistance should generally be between 4-15 ohms. If it's open-circuit or drops straight to zero, it's probably dead. If you have the means, start the engine and poke the signal wire with the multimeter; the voltage should fluctuate between 0.1 and 0.9V. If it's stuck at 0.45V without moving, it means the sensor isn't working. Inspecting the ceramic tip after removal is also telling: a grayish-white color is healthy, but if it's shiny black with particles, it's likely contaminated. Actually, repair shops use diagnostic tools to check the live data stream for the most accurate results, but doing a preliminary check ourselves can save a couple hundred bucks in diagnostic fees.
