EPS CM confirms driver’s driving intention by receving ENG rpm signal from PCM (Power train Control Module), or ECM(Electronic Control Module) while judging the failure of vehicle speed sensor. ESP use a maximum of 45A controlling ESP motor. If ESP motor is operating in idle, or engine rpm decreases due to abnormally high generator load, the engine stops or battery is discharged. To prevent this situation, When motor consume over 25A in engine idle, ESP CM grounds 12V voltage, which is outputted from ECU, and sends idle-up signal to engine ECU. If motor consume less than 20A, or vehicle speed is faster than 5Km/h, EPS CM turns "OFF" the idleup signal.