1 to 4 wire sensor illustration
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On 2 wire oxygen sensors, one wire is the sensor signal and the other is the sensor ground, also referred to as an I-EGO sensor (Isolated Exhaust Gas Oxygen Sensor). Both sensor signal wires are directly connected to one of the platinum-coated electrodes on the ceramic element. A 2 wire oxygen sensor is near identical to its predecessor, the 1 wire oxygen sensor. It was discontinued as it commonly became faulty because it relied on the sensor body/exhaust system as its ground, and, over time, the threads where the sensor screwed to the exhaust would corrode, resulting in a faulty ground. |
