If the real meaning of the engine P0231 Code is not found, you may use automobile meaning of the code for solving the car engine problem. The automobile dictionary meaning of the code is general meaning and you must not use general meaning as primary purpose. The automobile meaning of the engine code is P for Powertrain Code Problem is related engine, transmission and emissions systems. 0 for SAE – Generic. 2 for BBV Sensor Circuit Low Voltage. 3 for BBV Sensor Circuit Low Voltage and 1 for Transmission. Do not drive the car with the car engine problem and test drive is recommended when the car engine is fixed.