What are the four wires of an oxygen sensor?

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Four-wire oxygen sensor wires are: 1 black signal wire, 1 gray signal ground wire, and 2 white heater wires. Symptoms of a faulty oxygen sensor include: 1. Illumination of the vehicle's engine warning light; 2. Unstable idle; 3. Insufficient engine power; 4. Delayed acceleration; 5. Black smoke from the exhaust. Causes of oxygen sensor failure are: 1. Cracked ceramic element in the oxygen sensor; 2. Burned-out heater resistance wire; 3. Broken internal wiring of the oxygen sensor; 4. Engine control unit malfunction. The oxygen sensor uses a ceramic sensing element to measure the oxygen potential in the vehicle's exhaust pipe, calculates the corresponding oxygen concentration based on chemical equilibrium principles, and achieves the purpose of monitoring and controlling the combustion air-fuel ratio to ensure product quality and compliance with exhaust emission standards as a measuring component.