The automobile dictionary meaning for this P20D1 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. D for BBV Sensor Circuit Low Voltage and 1 for TFP Valve Position Switch-Drive Without Drive Ratio. The deactivation method of cylinders is realized by releasing a synchronizer pin that normally interlocks the cam follower and rocker arms. The P20d1 code resolutions the synchronizer pin is released using hydraulic compression which is measured by a dedicated solenoid. Do not use any false meaning for solving the car engine.