The engine P2645 Code lets you know about the car engine problem and this problem of the car engine should be fixed problem and real meaning of the car engine code is necessary to use. The real meaning of the code is found from manufacturer and automobile dictionary meaning of the code is found online and it is p for Powertrain Code Problem is related engine, transmission and emissions systems. 2 for MFG – Manufacturer Specific. 6 for Vehicle Speed Control And Idle Control System. 4 for BBV Sensor Circuit Low Voltage and 5 for Park/Neutral Position (PNP) Switch Circuit Engine Torque Signal Circuit.