What does code P0055 mean?

Q: What does code P0055 mean?

HO2S Heater Resistance (Bank 1 Sensor 3). P0055 indicates that the powertrain control module has detected an abnormal electrical resistance in the heater circuit of the downstream oxygen sensor on bank 1, which is sensor 3. The computer monitors the heater current and compares it to expected values; when the resistance falls outside the acceptable range, it sets this code and illuminates the check engine light.

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P0055

P0055HO2S Heater Resistance (Bank 1 Sensor 3)

P0055 indicates that the powertrain control module has detected an abnormal electrical resistance in the heater circuit of the downstream oxygen sensor on bank 1, which is sensor 3. The computer monitors the heater current and compares it to expected values; when the resistance falls outside the acceptable range, it sets this code and illuminates the check engine light.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.