The real meaning of the code is found from the car manufacturer and it is found in the car engine manual. However, the car engine P2621 Code is found in the car engine and get the real meaning of the code. The general meaning of the car engine code is p for Powertrain Code Problem is related engine, transmission and emissions systems. 2 for MFG – Manufacturer Specific. 6 for Vehicle Speed Control And Idle Control System. 2 for Air Conditioning (A/C) Clutch Feedback Circuit High Voltage and 1 for TFP Valve Position Switch-Drive Without Drive Ratio. You can learn many things from this code.