O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
The engine computer is seeing a very low signal from the rear oxygen sensor on bank 2. This usually means the sensor, its wiring, or the exhaust leak near it has a problem. It can also be caused by a fuel mixture issue or a bad heater circuit in the sensor.
The vehicle may still drive, but the problem can affect emissions, fuel economy, and how the engine computer monitors the catalytic converter. If the engine runs poorly, stalls, or other warning lights appear, diagnose it promptly.
P0157 means the powertrain control module has detected a low-voltage condition from the Bank 2 Sensor 2 oxygen sensor circuit. Bank 2 Sensor 2 is the rear O2 sensor on the bank opposite cylinder 1, usually located after the catalytic converter. The code points to an electrical or exhaust-related fault more often than a catalytic converter failure itself.
Not usually. P0157 points to the rear oxygen sensor circuit on bank 2, not directly to the catalytic converter.
Yes. Wiring damage, corrosion, or a loose connector is a common cause of this code.
No. If the wiring, connector, heater circuit, or exhaust has a problem, the code can come back after sensor replacement.
Usually yes for short-term use, but it should be diagnosed soon because it can affect emissions and fuel economy.