The P20B5 Code has a specific meaning according to the manufacturer of the car engine and car. The meaning of this code is not similar for all car engines. Different manufacturer put different meanings of the code according to the car model number. So, getting the manufacturer and car information is important. The dictionary meaning of the code is found online. The general meaning of the code is p for Powertrain Code Problem is related engine, transmission and emissions systems. 2 for MFG – Manufacturer Specific. 0 for Fuel And Air Metering. B for BBV Sensor Circuit Low Voltage and 5 for Park/Neutral Position (PNP) Switch Circuit Engine Torque Signal Circuit.