The engine P0155 Code gives idea about the car engine problem and it is necessary to know the accurate meaning of the engine code what you will find in the car engine manufacturer. You can read the automobile dictionary meaning of the engine code for fixing the car engine problem and it is P for Powertrain Code Problem is related engine, transmission and emissions systems. 0 for SAE – Generic. 1 for Transmission. 5 for TP Sensor Learn Not Complete and 5 for Park/Neutral Position (PNP) Switch Circuit Engine Torque Signal Circuit. The problem of the car engine can be started due to several causes.