Circuit Description
WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The DTC P0135 Heated Oxygen Sensor (HO2S) Heater Performance Sensor 1 diagnostic monitors operation of HO2S 1 heater circuit. The DTC P0141 HO2S heater performance sensor 2 diagnostic monitors operation of HO2S 2 heater circuit. Heaters in oxygen sensors increase amount of time the sensor spends in closed loop fuel control operation or catalyst monitoring operation. Oxygen sensor heater greatly reduces amount of time required for fuel control HO2S 1 to become active. Oxygen sensor heater is required by post-catalyst HO2S 2 to maintain high operating temperatures. Heater helps provide accurate oxygen content readings of engine exhaust by the HO2S.