The mileage is about 150 thousand km, with the 2005 Subaru forest 2.0T sports utility vehicle equipped with 4 automatic transmission. User reflection: the vehicle transmission does not lift. Inspection and analysis: the maintenance personnel tested and found that the speed of the vehicle was only 30 km/h when the engine speed reached 4000 r/min. Look at the transmission data flow and find that the gear is always in the 1 gear. Examination revealed that the transmission failure light was not lighted and there was no trouble code. Look again at the data flow of the transmission, and find that the data that is forced to drop the switch is not normal. Under normal circumstances, when the pedal is not stepped on, the switch should be closed, and when it is on the bottom, it will be connected. At this time, the state is not connected to the accelerator pedal. Remove the forced drop switch and use the multimeter to measure the 2 terminals. It is found that it is on state and indicates that it is invalid. Troubleshooting: replace the forced drop switch, confirm the trouble shooting. Review and summary: the control mode of the vehicle transmission is different from that of the model after 2006, the latter is to use the throttle position signal to realize the forced fall, so the car will not appear. Before the vehicle starts, the forced drop switch is connected, so the transmission will not naturally lift.