2021 Mercedes-Benz AMG GT Brake Groaning/Honking Noise TSB

Symptoms

Owners of the 2021 Mercedes-Benz AMG GT may notice a specific Mercedes-Benz AMG GT brake noise emanating from the vehicle's braking system. This sound is characterized as a distinct groaning or honking noise. The TSB specifies that this particular noise typically manifests when the vehicle is traveling at low speeds and the driver applies only light brake pressure. This condition is distinct from other brake noises that might indicate a problem.

Mercedes-Benz further categorizes these symptoms under general brake system noises within the chassis/suspension group. Specifically, the TSB references 'Noises > General,' 'Noises > Creaking,' 'Noises > Whirring/howling,' and 'Noises > Makes noise' as descriptive categories for this type of brake sound.

Diagnosis and Trigger Conditions

The root cause of this Mercedes-Benz AMG GT brake noise has been identified as frictional vibrations. These vibrations occur between the brake pads and rotors, particularly when very light brake pressure is applied, leading to subtle modulations in friction. This interaction results in the characteristic groaning or honking sound reported by owners.

According to the TSB, this condition is not unique to a few vehicles; it can be duplicated on most Mercedes-Benz AMG GT models. To validate that the noise is indeed normal, service technicians are advised to use a 'like for like reference vehicle' for comparison. This process helps confirm that the observed noise falls within the expected operational characteristics of the braking system under these specific conditions.

Important Warnings for Owners

A critical piece of information for owners of the 2021 Mercedes-Benz AMG GT is that this groaning or honking brake noise is explicitly stated by the manufacturer to be 'normal behavior under the conditions listed.' This means the sound does not signify a fault, malfunction, or impending failure of the braking system.

The TSB clarifies that the noise is induced by 'normal brake pad and brake rotor vibrations' that occur when very light brake pressure is applied. Furthermore, Mercedes-Benz issues a direct warning: 'Exchanging brake components will not rectify' this condition. This crucial advisory prevents unnecessary repairs, as replacing brake pads, rotors, or other related components will not eliminate this specific, normal operational noise.

What Owners Should Do

If you own a 2021 Mercedes-Benz AMG GT and encounter this specific Mercedes-Benz AMG GT brake noise—a groaning or honking sound at low speeds with light brake pressure—you can be assured that, according to Mercedes-Benz Technical Service Bulletin LI42.10-P-079904, this is a normal characteristic of your vehicle. There is no need to seek a repair for this particular noise, as it is not indicative of a defect.

It is important to heed the manufacturer's warning that attempting to replace brake components will not resolve this specific sound. However, if you experience any other types of unusual brake noises, a noticeable change in your vehicle's braking performance, or if any brake-related warning lights illuminate on your dashboard, it is always prudent to have your vehicle thoroughly inspected by a qualified Mercedes-Benz service technician.

Source: NHTSA ID: 11024405