Code Definition

P0057 — HO2S Heater Control Circuit Low (Bank 2 Sensor 2)

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0057

P0057 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0057 is stored, the module has detected a signal or supply voltage lower than the expected operating range; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0057 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0057 code signifies a low voltage condition in the heater control circuit of the downstream oxygen sensor (Bank 2 Sensor 2), which is located after the catalytic converter. The heater element in the oxygen sensor is essential for rapidly bringing the sensor to its operating temperature following engine startup. The Engine Control Module (ECM) sets this code when it detects a lower than expected voltage in the heater circuit, potentially impairing the sensor's ability to accurately assess the exhaust gas composition for effective engine management.

Quick Facts