A Honda Accord sedan, the car when the engine speed "speed" by asking the user, that this car is often his wife, he just occasionally open, but every time he has a "call" sound. For which the car replaced the spark plug and some spare parts did not solve the problem.
    According to the previous maintenance experience, the car's knock control function is to have the engine control unit through the collection throttle position sensor and engine speed sensor signal, the use of "adaptive online search method" to control the ignition timing. In addition, the car's automatic transmission control unit uses a "fuzzy logic control", he will choose the best shift point according to the driver's habit.
    After understanding the above control methods and user-provided information, the car's fault can be said to be the truth. Because the car is equipped with automatic transmission for the electronic control, such transmission control unit (ECU) in order to improve fuel economy and driving comfort. Will automatically change the transmission shift point according to the driving habits of the driver, and (ECU) will save the data again. As the driver of the car driving speed is relatively slow, the transmission has been adapted. Once replaced by a driver driving faster, the ECU can not immediately learn the current driver's driving habits and change the data that was previously stored. Since the ECU can not immediately find the appropriate change point, the transmission actually performs the gear ratio The desired gear is required to be high, resulting in increased engine load. At this time the engine "knock" control can not immediately come to adapt, resulting in false fault.
    After understanding the cause of the trouble, after 50 km of rapid acceleration exercise, the engine 'call rod' sound disappeared.