Why does the Mercedes-Benz C-Class have a current sound?
2 Answers
Mercedes-Benz C-Class may produce a current sound when the HOLD function is activated, and there may also be a current sound at the wireless charging area. HOLD function activation: This is due to an issue with the ESP hydraulic unit, where the sound is generated by the solenoid valve operating under oil pressure. The solution is to replace the brake fluid or the ABS pump. If replacing the brake fluid, set the filling pressure of the brake fluid filling machine to 1.2bar and bleed the brake system in the order of right rear, left rear, right front, and left front. Wireless charging area: The sound comes from the fan beneath the charging area, which operates when the temperature exceeds 30 degrees. This is unrelated to the interior temperature of the car but is influenced by the temperature of other components near the exhaust pipe underneath. The fan starts when the temperature rises.
As a long-time driving enthusiast, the electric buzzing sound in the Mercedes-Benz C-Class is quite common. I've personally encountered it several times, such as hearing a faint humming noise when stopped at a red light, which is mostly normal operation of electronic components. It could come from the cooling fan in the engine compartment, which emits a slight electric sound when dissipating heat, or from the brake booster system during operation. The audio module is also a frequent source, especially after turning on the sound system. However, the issue arises when the sound becomes louder, sharper, or irregular, which may indicate aging wiring, burnt relay contacts, or loose grounding. I recommend first trying to identify the source of the sound—listening quietly near the engine compartment or dashboard after starting the engine can help locate it. Regular maintenance can prevent minor issues from developing into faults. The Mercedes electronic system is sophisticated, and ignoring electric sounds may lead to more expensive repairs. If the sound is accompanied by a warning light, it's essential to visit a dealership for inspection and diagnosis.
