P1155 LEXUS, SCION, TOYOTA: AIR/FUEL RATIO SENSOR HEATER CIRCUIT MALFUNCTION BANK 2 SENSOR 1
POST UPDATED IN June, 2023
P1155 LEXUS, SCION, TOYOTA: AIR/FUEL RATIO SENSOR HEATER CIRCUIT MALFUNCTION BANK 2 SENSOR 1
The PCM (Powertrain Control Module) requires accurate air/fuel mixture readings to optimize fuel economy as well as emissions. If an inaccurate reading is sent to the control module, the amount of fuel required may not be enough or may exceed the required. That’s why many current model manufacturers use A/F (Air/Fuel) Sensors instead of conventional oxygen sensors. An A/F Sensor can read in a wider and narrower range of fuel mixtures.
The A/F Sensors have a heater that helps them get the temperature needed for good performance. A dedicated circuit controls the heater and using a pulse modulation, it regulates the temperature of the sensor, taking this action accurately. In Toyota cars, the PCM sends a reference signal corresponding to 3.0 v to the A/F Sensor. A detection circuit within the PCM monitors the changes in current flow and produces an output voltage signal proportional to the air/fuel mixture.
The setting of fault code P1155 OBDII for the manufacturers Lexus, Scion, and Toyota indicates that the heater circuit of the Air/Fuel Ratio Sensor 1 of bank 2 has experienced unstable operation.
The diagnostic code P1155 OBD2 is set because of the following reasons:
The steps to solve the DTC code P1155 OBDII are the following: