Why does a Mercedes-Benz suddenly not accelerate when the accelerator is pressed while driving?
2 Answers
Mercedes-Benz not accelerating when the accelerator is pressed while driving may be due to the following reasons: 1. Faulty throttle position sensor. When the accelerator is pressed, the cable moves the throttle, which has a position sensor. The control unit uses the signal from the throttle position sensor to determine the throttle opening, calculates the corresponding signal voltage, and then uses this voltage to determine the fuel injection amount. 2. Issues with the engine's fuel system. Using low-quality gasoline can lead to fuel pump burnout, catalytic converter failure, piston problems, etc., directly affecting engine power and causing issues like engine stalling or failure to accelerate. 3. Ignition system failure. Ignition high-voltage wires rarely have issues; the main problems usually lie with the ignition coils and spark plugs, which are wear-prone parts. Poor performance or the use of inferior spark plugs can result in weak acceleration or shaking during acceleration.
My old Mercedes-Benz C-Class had the same issue last year—suddenly lost throttle response while cruising on the highway, forcing me to pull over in panic. The mechanic diagnosed it as a failed throttle pedal sensor and explained that Mercedes' electronic throttle system triggers a protective speed limiter upon detecting faults. It could also signal a failing fuel pump—insufficient fuel delivery saps power. Severe carbon buildup choking the throttle body can similarly cause breathlessness. Since that repair, I’ve wisened up: every maintenance now includes fuel system cleaning checks. Especially with finicky German cars, sketchy roadside repairs risk complications—best to head straight to the dealership for computer diagnostics.
