The dictionary meaning of the P20BF Code is p for Powertrain Code – Problem is related engine, transmission and emissions systems. 2 for MFG – Manufacturer Specific. 0 for Transmission. B for BBV Sensor Circuit Low Voltage and F for TFP Valve Position Switch-Drive Without Drive Ratio. This general information is general and it does not help you to solve the car engine problem. For solving the car engine problem, real information is necessary to use. The real information is available in the manual of the car engine what is set by the manufacturer. If real information of the code is unknown, then problem cannot solved.