The engine P2031 Code is setup in the car engine by the automobile manufacturer. The engine code is very important thing. If you do not know the real meaning of the code, you cannot fix the car engine. The automobile dictionary meaning of the code also helps for solving the car engine. The automobile 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 Fuel And Air Metering. 3 for Cruise Control Servo Indicates Low and 1 for TFP Valve Position Switch-Drive Without Drive Ratio.