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Q: Throttle suddenly goes out

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Recently I have been having trouble with the throttle on my car. Suddenly it would go out, without any warning. Fortunately all I had to do was restart it for it to operate again. Eventually, I replaced the gas pedal assembly. Since then, the problem has occurred twice. I just reset it by restarting and never press fully on the pedal down to the kick-down position. If I were to fully press down, the throttle would become inoperable. Recently the front brake pads, plus the inner and outer wheel bearings were replaced. I also turned the rotors. But the car will not drive after performing that reassembly. When I accelerate, after a second or two the yellow ESP light comes on and my vehicle loses throttle. It accelerates strongly for a second when I turn the ESP switch to Off. Then the yellow triangle light comes on and I lose all throttle. I cleaned the right wheel sensor and also added dielectric grease in it. For five minutes I left the ignition on, untouched. Then rotated the steering wheel, left to right, three times. But it will not drive! When I took it apart to do the front brakes, except for the throttle problem, it drove fine. In your review of my information, what advice can you give me to solve the problem?

Hi there, thank you for asking about your 2003 Mercedes-Benz S55 AMG. This is usually caused by a failing throttle body. The throttle motor or sensor fails and will cause this to occur. If the motor cannot move the throttle plate to the position that the computer is requesting then this will occur. It can also be caused by another sensor such as the air flow meter, but that is not as common. The accelerator pedal can also cause this if the sensor on it is not reading properly. Before changing anything I scan the computer for codes and monitor the signals from all of the sensors to see if anything is reading incorrectly. If you need help, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair a failing throttle body.

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