General Description

The oxygen sensor-1 is installed on the exhaust manifold (precatalyst) and the oxygen sensor-2 is installed on the exhaust pipe (post catalyst). Each sensor detect the concentration of oxygen in the exhaust gases.

ECM (PCM) detects the air-fuel ratio of the mixture supplied to the engine by monitoring the signal (output voltage) from sensor-1.The signal (output voltage) from sensor-2 is used to detect malfunction of the three way catalytic converter.

Each oxygen sensor heater promotes activation of the oxygen sensor.