The general meaning or the automobile dictionary meaning of the car engine P2120 Code is important when the right meaning of the code is not found. 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. 1 for Transmission. 2 for Air Conditioning (A/C) Clutch Feedback Circuit High Voltage and 0 for Transmission Engaged At High Throttle Angle. You need to find the real cause of the car engine’s problem and fix the car engine by the real meaning of the code. You must allow an automobile engineer to fix the car engine.