P1157 BUICK, CADILLAC, CHEVROLET, GMC: HO2S BANK 2 SENSOR 2 LEAN SYSTEM OR LOW VOLTAGE
POST UPDATED IN February, 2023
P1157 BUICK, CADILLAC, CHEVROLET, GMC: HO2S BANK 2 SENSOR 2 LEAN SYSTEM OR LOW VOLTAGE
An Oxygen Sensor (HO2S) is a device that is used to adjust the air/fuel mixture. It also checks how efficient the TWC (Catalytic Converter) is. This type of sensor measures how much oxygen is present in the exhaust and sends this data to the ECM (Engine Control Module). For accurate readings, the oxygen sensor must reach the necessary temperature. For this reason, they have a heater that decreases the time required to reach that temperature.
The HO2S receives from the Engine Control Module 450mV reference. After starting the engine for the first time, the ECM activates the open-loop function and ignores the sensor voltages. When the Oxygen Sensor works at the required temperature, the ECM operates in a closed-loop, and the sensor sends a signal from 0 to 1,000mV.
The P1157 OBD2 fault code setting occurs when the ECM finds the voltages are excessively below the allowed values in the Oxygen Sensor 2 circuit of bank 2.
The P1157 OBDII diagnostic code is set for the following reasons:
Consider these suggestions to solve the DTC P1157 OBD2 code: