The dictionary meaning of the B2321 Code is B for Body Code Problem is antilock brake system, electronic suspension and steering 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. It seems that the body of the engine has the problem and it is not necessary to change any component for solving the car engine. Even it is cheap for solving the car engine problem easily. Do not drive the car with the problem.