Code Definition

P0055 — HO2S Heater Resistance (Bank 1 Sensor 3)

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

About P0055

P0055 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 P0055 is stored, the module has detected 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 P0055 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 P0055 code indicates a problem with the heater element's resistance in the oxygen sensor identified as Bank 1 Sensor 3. This sensor is typically the third sensor in the exhaust system on Bank 1 and may be found in vehicles with more complex exhaust configurations. The Engine Control Module (ECM) triggers this code when it detects that the resistance of the heater element in the oxygen sensor is out of the specified range. The heater element is crucial for quickly bringing the oxygen sensor to its operational temperature, which is necessary for accurate exhaust gas analysis.

Quick Facts