The temperature of the automatic transmission fluid may rise too high depending on the driving conditions, because there is a glitch in the program of the ECU for automatic transmission, and also because for vehicles with electric fan-type automatic transmission fluid cooling systems the fluid temperature sensor for the electic fan is not installed into the connector with the correct depth. If this occurs and the illuminated warning light is ignored, the automatic transmission fluid loses some lubricating capacity, and the rotary parts inside the transmission can be worn and damaged, which could cause the driving force to decrease, and in the worst case this could cause the vehicle to stall.