DTC P0133: O2 Sensor Circuit Slow Response (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 HO2S heater greatly decreases the amount of time required for fuel control to become active. The ECM/PCM provides a pulse width modulated control circuit to adjust current through the heater. When the HO2S is cold, the value of the resistance is low and the current in the circuit is high. Conversely, if the temperature in the resistor of the sensor rises, the current drops gradually.