An oxygen sensor is tested using a digital multimeter's MIN/MAX function. The readings are a minimum of 78 mV, a maximum of 932 mV, and an average of 442 mV. Technician A states that the engine is operating normally, while Technician B claims that the oxygen sensor reading is skewed toward rich. Which technician is correct?
Physics · High School · Thu Feb 04 2021
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Answered on
- Technician A is correct as the oxygen sensor readings suggest that the engine's fuel management system is functioning normally by transitioning between rich and lean conditions. An oxygen sensor's voltage reading fluctuates between approximately 100 mV (lean) to 900 mV (rich) when the engine is running properly. A reading of 78 mV indicates a lean condition (more oxygen, less fuel), while a maximum of 932 mV reflects a rich condition (less oxygen, more fuel). The average voltage (442 mV) being roughly in the middle is a good sign as it indicates the sensor is responsive and the engine control system achieves a balance between rich and lean mixtures over time.
- Technician B's statement that the oxygen sensor reading is skewed toward rich does not seem to be supported by the data provided. The minimum value of 78 mV shows that the sensor is detecting lean conditions as well, which would not be the case if the sensor was biased towards rich readings. Hence, based on the data given and without further context or information, Technician A's assessment is more accurate.