DTC P0150-00: O2 Sensor Circuit (Bank 2/Sensor 1): General Description

The lambda sensor that installed at upstream and downstream of exhaust manifold sends the current and voltage which generated from the O2 density of exhaust gas to ECM.

The upstream lambda sensor (S1) that installed in front of catalytic converter is a linear lambda sensor it measures the O2 density of exhaust gas for fuel correction. ECM controls the pumping current for lambda sensor to have the characteristic at lambda (λ) value of 1.0. The O2 density is calculated with control value. The performance of linear lambda sensor is most active at normal operating temp. (450°C~600°C). In order to reach the normal temp. quickly and maintain the temp., the heater (Heating coil) is integrated in lambda sensor. The heater is controlled by PWM signal from the ECM.

The lambda sensor that installed at the end of catalytic converter is multilayer structure type of sensor that consist of Zirconia and Alumina. The sensor generates the about 1 V of voltage when the density difference between the reference O2 density and the O2 density of exhaust gas is high. If the difference is low, then the voltage output is close to 0 V. In order to lambda sensor to generate the voltage, the certain temperature must be maintained. To maintain the temp., the heater (heating coil) is integrated in lambda sensor and the heater is controlled by PWM signal from the ECM.