How to Measure an Oxygen Sensor?
2 Answers
Oxygen sensor measurement methods include: 1. Multimeter voltage measurement: Maintain engine speed at approximately 2500 rpm for about 90 seconds, then measure the voltage at the oxygen sensor signal output terminal using a multimeter; 2. Oxygen sensor tester inspection: Determine whether the sensor is functioning normally by observing the flashing pattern of the indicator lights on the oxygen sensor tester; 3. Multimeter resistance measurement: Utilize the resistance characteristics of the oxygen sensor to measure its resistance values in both warmed-up and non-warmed-up states to assess potential damage. The oxygen sensor is a crucial feedback component in electronic fuel injection engine control systems, playing a key role in controlling vehicle exhaust emissions, reducing environmental pollution, and improving fuel combustion quality in automobile engines.
The measurement core of the oxygen sensor lies in its output voltage signal. During operation, the zirconia element on the sensor generates a voltage, the magnitude of which depends on the oxygen content in the exhaust. The sensor's condition can be determined by measuring the voltage on the signal wire with a multimeter. During cold starts, the signal may be unstable, but after warming up, the normal value should fluctuate rapidly between 0.1-0.9V. If the voltage remains stuck at 0.45V for a long time or exceeds this range, it's highly likely that the sensor is faulty. I often use the analog testing method: disconnect the vacuum tube to create a rich mixture state, and the voltage should rise; spray cleaner to create a lean mixture, and the voltage should drop. If it doesn't, the sensor should be replaced.
