DTC P0135-00: O2 Sensor Heater Circuit (Bank 1/Sensor 1): General Description

The normal operating temperature of the Heated Oxygen Sensor (HO2S) ranges from 350 to 850°C (662 to 1562°F). The Heated Oxygen Sensor (HO2S) heater greatly decreases the amount of time required for fuel control to become active. The PCM provides a pulse width modulated control signal to adjust current through the heater. When the Heated Oxygen Sensor (HO2S) is cold, the value of the resistance is low and the current in the circuit is high. On the contrary, if the temperature in the resistor of the Heated Oxygen Sensor (HO2S) rises, the current drops gradually.