The meaning of the P20B4 Code is important for solving the car engine and you can get the real meaning of the code from the manufacturer but general meaning is available online. The general meaning of the code does not provide much information accurately. That is why, read the manual of the car or get meaning of the code according to the manufacturer and model number of the car. Do not try to fix the car according to the automobile dictionary meaning. You cannot solve the problem from the car engine and you may deliver more problem in the car engine.