Fault phenomenon
    1996 BMW 750iLE38 European regulation models, M73 engine with electronic throttle EML system. Driving a sudden step on the accelerator pedal did not respond, turn off the engine, restart, still can not accelerate. Helpless the car to the repair shop.
    Fault repair
    The car uses CNC injection system M5.2 version, ignition injection control, and canceled the throttle cable, the computer through the accelerator pedal opening sensor to perceive the driving intention. Preliminary analysis, the car fault in the electronic throttle EML system.
    Connect GT1 to EML system to read the fault code, the diagnostic instrument shows "acceleration pedal opening sensor failure", and the fault code can not be cleared. Go to the "Dynamic Data" item and find "Accelerator pedal opening" is 0.
    According to the circuit diagram to check the line is not short circuit, open circuit failure, then replace the "accelerator pedal position sensor". But in the matching sensor appeared "section outside the raw branch" thing. Several times the diagnostic device always displays "sensor match error", but the fault code is no longer present. In the match, the diagnostic device GT1 will prompt you to completely depress the accelerator pedal. It is suspected that the second sensor signal needs to be identified at the time of the match. This is the "forced downshift switch KickDown".
    Remove the accelerator pedal to find the forced downshift switch has been lost. Because the order has been too late, think of the vehicle can also be normal before the ride, so the following methods to match: take a system "single throw normally open switch", installed to the "forced down switch" plug, matching will accelerate the pedal After stepping on, press the switch immediately and release the accelerator pedal. After the successful completion of the match, the failure disappears.
    Maintenance summary
    As the BMW 750iL using V12 engine, power is quite strong. Ordinary driving, there is no need to step on the accelerator pedal in the end, so cover up the "forced down switch" lost fault. The fault does not affect driving, but when matching the "accelerator pedal opening sensor", it is necessary to recognize the signal of the switch, resulting in a "match error". In the actual circuit structure, the "forced downshift switch" signal is determined by first inputting the "electronic throttle control module EML" and then sharing the data via the network.