The error meaning of the diagnosis P0172 Code may make trouble in the car engine. That is why, you must not follow automobile dictionary meaning of the code. You can find the automobile dictionary meaning of the code online and the automobile dictionary meaning of the code is p is Powertrain Code Problem is related engine, transmission and emissions systems. 0 is SAE – Generic. 1 is Transmission. 7 is Vehicle Speed Output Circuit and 2 for A/C System High Pressure High Temperature. You should verify the car engine and identify the reason of the car engine problem by following symptoms.