Fault phenomenon: a Nissan steed car, the car runs 120 thousand kilometers, the owner describes: the car after the cleaning of the electronic throttle body, the phenomenon of excessive idle speed (1500rpm), the car for two days, the idle speed is too high, broken battery or no effect. Fault diagnosis: in this case, the learning of electronic throttle body is usually completed, and idling speed will come down. The learning setting method is divided into three steps: accelerating pedal release location learning, throttle closed position learning and idle air volume learning. The acceleration pedal release position learning accelerates the pedal release position learning operation by monitoring the acceleration pedal position sensor output signal and learning the position when the accelerator pedal is completely released. This operation must be performed every time when the accelerator pedal position sensor or the wiring harness plug of ECM is disconnected. The operating procedures are as follows: 1. confirm that the accelerator pedal is completely released; 2. turn the ignition key to ON position for at least 2 seconds; 3. turn the ignition switch to the OFF position for at least 10 seconds; 4. to turn the ignition key to the ON position for at least 2 seconds; 5. to turn the ignition switch to the OFF position for at least 10 seconds; the throttle position is closed. Learn the operation of the throttle valve closing position, and monitor the throttle position sensor output signal to learn the position of the throttle valve when it is completely closed. This operation must be performed every time the wire harness plug of the electronically controlled throttle control actuator or ECM is disconnected. The operating procedures are as follows: 1. confirm that the accelerator pedal is completely released; 2. switch the ignition switch to the ON position; 3. turn the ignition switch to the OFF position for at least 10 seconds; 4. confirms that the throttle action is over 10 seconds through the throttle action sound. Idle air volume learning idle air volume learning operation purpose, so that the engine speed is maintained within the specified range of idle air intake. This operation must be carried out following the following cases: (1) every time the electric control throttle control actuator or ECM is replaced; (2) idle speed or ignition is outside the specified range; before the idle air is studied, the following conditions are satisfied: the voltage of the battery is greater than 12.9V (idle speed); Coolant temperature: 70~100 centigrade (158-212) PNP switch: ON; electrical load switch: OFF (air conditioner, front headlight, rear window mist eliminator); steering wheel: middle position, straight forward position; stop speed stop; the gearbox has been preheated; (1) that is, if there is any one in a moment. If the piece is not satisfied, the learning operation will stop. (2) for the automatic transmission model using the CONSULT-II diagnostic instrument, the FLUID TEMP oil temperature sensor of the driving vehicle until the DATA MONITER data monitoring model shows a lower than 0.9V. (3) driving vehicles for 10 minutes for automatic transmission models without CONSULT-II diagnostic devices and manual transmission models. Learning methods for idle air volume are as follows (do not use CONSULT-II diagnostics): 1. perform "acceleration pedal release position learning"; 2. perform "throttle closed position learning"; 3. start the engine and increase the engine temperature to normal operating temperature; 4. check whether all items are listed in the precondition before the premise conditions. All is ready; 5. switch the ignition switch to the OFF position, wait for at least 10 seconds; 6. determine the accelerator pedal completely release, the ignition switch to ON position to wait 3 seconds; 7. in 5 seconds to repeat the following operation 5 times quickly; A. completely stepped down the accelerator pedal; B. completely released the accelerator pedal; 8. wait 7 seconds, completely stepped down the accelerator pedal. The board keeps this state for about 20 seconds until the MIL stops flashing and brightening; 9. after the MIL brightens, the accelerator pedal is completely released in 3 seconds; 10. starts the engine idle running; 11. is waiting for 20 seconds. Description: (1) it is best to use the clock to accurately timing; (2) if the accelerator pedal position sensor circuit fails, it will not be able to turn on the diagnostic mode.