The dictionary meaning of the P20BD Code is not helpful for solving the car engine. You will get the general idea about the problem of the car engine from the automobile dictionary. The automobile dictionary is found online what you can use to get information but do not use that information for solving the problem. The dictionary meaning of the code is P for Powertrain Code – Problem is related engine, transmission and emissions systems. 2 for MFG – Manufacturer Specific. 0 for Transmission b – BBV Sensor Circuit Low Voltage and d is TFP Valve Position Switch-Drive Without Drive Ratio.