Symptom: a Jetta Metropolitan Pioneer AT car, the user reflects the car in the process of driving, the engine speed table reached 3000-4000r / min, while the vehicle speed is only 30 km / h.
    Troubleshooting: Use the diagnostic tool V. A. G1552 in the automatic transmission control system for fault code 00518, the fault is the throttle potentiometer G69 signal beyond the allowable value. The car with a two-column lift lift, the transmission hanging D block throttle, observe V. A. G1552 data block 003 group third zone, see the gear from 1H (1 block machine) to 2H (2 block machine) repeated changes. That is to say that the gear is only jump from 1 block to 2 block, and back to a block. At this time to read the automatic transmission data block 001 group 2 zone throttle potentiometer voltage value, no matter how much the throttle to open, always show 3V. Use V at this point. A. G1552 into the engine control system for the fault code 00518, read the data block 001 group 3, no matter how to change the valve angle of the display value is always 57 °.
    Since the automatic transmission electronic control unit is automatically shifted according to the transmission speed signal and the throttle potentiometer signal, if the control unit can not receive the throttle potentiometer signal or the throttle potentiometer signal is always a fixed data, the automatic transmission computer It is necessary to implement the emergency operation procedures, this time the vehicle driving situation is described above. By checking the fault code and reading the data block are described throttle potentiometer G69 damage.
    After replacing the throttle assembly, has made the engine and automatic transmission electronic control system of the basic adjustment of the throttle. And then road test, observe the engine speed at 3000r / min, the corresponding speed of 100km / h, the transmission is in the D block in the 4 block operation, this situation shows that the white dynamic transmission work completely normal.