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How the Active Hood Works on a Mercedes

Model: Mercedes Classe C W204 - Years: 2007, 2008, 2009, 2010, 2011, 2012, 2013
Part: Warning light – error code

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The active hood system is designed to protect pedestrians in the event of a frontal impact: when sensors detect a collision with a pedestrian, the hood instantly lifts a few inches, creating space between the hood and the rigid engine components. This reduces the severity of the impact on the pedestrian's head.

The main components are the pedestrian sensors mounted in the front bumper, one on the right and one on the left. They measure the acceleration and force of the impact on the bumper.

In the case of the video, the left one was physically broken: Another component is the ECU that processes the sensor signals, and the pyrotechnic (or mechanical) actuators located near the hood hinges; when they receive the signal from the ECU, they explode like an airbag to lift the hood, which is designed with deformable areas to absorb energy.

When the hood is activated, the system must then be reset, and the actuators must be replaced.

If, as in the case of the video, the sensor is broken, the ECU detects the anomaly and triggers the error light.


Posted on 7 June 2026 by ScegliAuto


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Where is the Reset Button for the Tyre Light on a Hyundai Ix35?

The instrument cluster of the Hyundai Ix35 is equipped with a tyre light that illuminates to alert the driver of low pressure in one or more tyres. In addition to simply having a flat tyre, there could also be a puncture or a malfunction of the monitoring sensor. Once the nature of the problem is determined and resolved, you can quickly reset the tyre light by pressing the button depicting a flat tyre, located on the left side of the steering wheel, for a few seconds, waiting for the warning to turn off on the instrument cluster.

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by ScegliAuto

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