Why does a Mercedes-Benz suddenly not accelerate when the accelerator is pressed while driving?

[LaVincent]

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.

[SanJameson]

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.

[StGabriela]

With over a decade of experience in auto repair, Mercedes-Benz owners often complain about this issue. First, check if the electronic throttle is dirty—excessive carbon buildup can affect air intake. Then, test whether the throttle pedal sensor's data stream is abnormal. I've encountered cases where the transmission temperature was too high, automatically limiting power, especially in older dual-clutch models. There's also a hidden problem: the low-pressure fuel pump filter screen gets clogged, causing insufficient fuel supply and engine failure. If you can't handle it yourself, use a diagnostic tool to read the fault codes and check if the engine control module reports errors. It's recommended to tow the car to a workshop for systematic troubleshooting—don't force it and risk damaging the catalytic converter.

[HaleyDella]

Don't panic when encountering this situation while driving. First, release the accelerator and gently press it a few times to test. If it fails, immediately turn on the hazard lights. After pulling over, do not turn off the engine; check if the engine warning light is on the dashboard. It's likely a fuel system issue or sensor malfunction causing power loss. Remember, if you turn off the engine, it might not start again, so directly call for roadside assistance to tow the car. Last week, my colleague forced it to drive, resulting in a completely ruined transmission. Replacing a new one for a Mercedes costs around fifty to sixty thousand. Safety always comes first.

[LaAbel]

Mercedes' electronic throttle system is quite complex. When you press the accelerator, it actually sends electrical signals to the computer to control the throttle opening. Poor contact in the signal wires can cause sudden disconnections, making the engine think you want to stop. For example, water ingress and corrosion in the main wiring harness connector are particularly common. There's also the issue of a failed mass airflow sensor, causing the computer to miscalculate the fuel injection amount. The mechanic who helped me last time used an oscilloscope to detect signal interference problems. If you encounter this, try disconnecting the battery for a few minutes to reset the computer—sometimes temporary faults can disappear. However, in the long run, you need to check whether the seals on each connector have aged.

[JulianAnn]

It's really frustrating to encounter throttle failure during the commute. My E-Class once had this issue in traffic. Later, I found out it was caused by poor fuel quality leading to injector gumming up, and switching to 95-octane fuel solved the problem. Minor maintenance issues that are usually overlooked can also cause trouble, like an air filter not being replaced for three years, causing the engine to suffocate. Also, older Mercedes-Benz cars are particularly prone to dirty throttle bodies, so it's recommended to clean them every 20,000 kilometers. Taking the car to a repair shop to read the fault codes can help; in most cases, spending a few hundred yuan to fix the sensor or clean carbon deposits will do the trick, but don't wait until the car completely breaks down.