The general meaning of the P20D9 Code is not necessary thing. You need to get the real meaning of the code what you can find from the manufacturer’s meaning. Do not use the general information for solving the car engine. It may make more trouble. 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. D for BBV Sensor Circuit Low Voltage and 9 for A/C System High Pressure High Temperature. However, it is easy to solve the car engine problem.