Circuit Description

Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to the ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. If DTC P1128 is present, ECM turns off power to throttle motor and magnetic clutch and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects a locked throttle control motor. Possible causes are:

• Defective throttle body assembly.
• Defective throttle control motor.
• Defective ECM.