DTC P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1); DTC P0032 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1): Description

Refer to DTC P2195  .

HINT:

• When either of these DTCs is set, the ECM enters fail-safe mode. The ECM turns off the Air Fuel Ratio (A/F) sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned to OFF.
• Although the DTC titles say the oxygen sensor, these DTCs relate to the A/F sensor.
• Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
• The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The A/F sensor heater circuit uses a relay on the +B side of the circuit.

Fig 1: Air Fuel Ratio Sensor System Diagram (Bank 1 Sensor 1)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

• Sensor 1 refers to the sensor closest to the engine assembly.
• Sensor 2 refers to the sensor farthest away from the engine assembly.