Oxygen (O2) Sensor (B2)
Oxygen (O2) Sensor is mounted at the front and rear of a catalyst converter and delivers current and voltage that are generated based on oxygen levels in exhaust gases to the engine Electronic Control Unit (ECU).
The O2 Sensor (S1), installed at the front of the catalyst converter, is a linear lambda sensor that computes the oxygen levels of the exhaust and adjusts fuel volume. The linear lambda sensor determines the oxygen concentration levels (lambda (λ) value) in exhaust gases by monitoring the change in current. The rear O2 Sensor (S2) is a multi-layered membrane sensor made of zirconia and alumina. The sensor determines the oxygen concentration levles in the air and in exhaust gases by comparing the voltage differences between the two.
In order to reach the normal operational temperature and maintain it, the system is equipped with a heater (heating wire) controlled by the PWM and the engine ECU.