The car engine P2321 Code lets you know about the car engine. By the real meaning of the code, you can understand the real cause of the car engine problem. You can also use the automobile dictionary meaning of the code when you need to use it actually. 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. 3 for IC Module 4X Ref Circuit Intermittent, No Pulses. 2 for Air Conditioning (A/C) Clutch Feedback Circuit High Voltage and 1 for TFP Valve Position Switch-Drive Without Drive Ratio.