A Lexus ES300 car with mileage exceeding 200 thousand km, equipped with 1 MZ-FE engine and A540E automatic transmission. User response: put the gear lever into the D position, and the vehicle can not move forward. Only by pressing the accelerator pedal can you drive. The speed of the vehicle is faster than 120km/h when the engine speed is above 3000r/min, and the fault lights of the dashboard are lit. After receiving the car: using the diagnostic instrument to self diagnose, there are two fault codes: P0753 and P1765. The meaning of the fault code P0753 is the A fault of the shift solenoid valve. The meaning of the fault code P1765 is accumulator pressure control solenoid valve malfunction. Analysis of the cause of failure code, may be line contact is bad or solenoid valve itself is bad. Unplug the wiring harness plug of the solenoid valve for checking. The terminals are reliable and no oxidation. Check the line, no exception is found. The automatic transmission has 4 solenoid valves, namely the shift electromagnetic valve A, the shift electromagnetic valve B, the locking clutch solenoid valve and the pressure control solenoid valve. The resistance of the two shift valves is measured around 14 ohms, normal. Clear the trouble code, carry out the road test, and the fault lights go out normally. Stop the vehicle, move the shift lever from P to L position several times, the engine fault light is lit, and the O/D indicator lights flicker. The fault code is transferred, and the fault code is still P0753 and P1765. Unplug the wiring harness plug of the engine and transmission control unit, and measure the resistance of the 4 solenoid valves at the wiring harness plug, and the result is normal.