2023 Mercedes-Benz AMG C43

I am filing a safety complaint regarding my 2023 Mercedes-Benz AMG C43 4MATIC. The vehicle has approximately 23,000 miles. On multiple occasions, the vehicle has abruptly and violently applied the brakes and/or come to a near stop while I was driving on highways and side roads, even though there was nothing in front of me that should have triggered emergency braking. There was no vehicle, pedestrian, cyclist, object, or road hazard present that would justify this braking event. This is not normal braking behavior. The car essentially performs an uncommanded emergency stop or severe deceleration without warning. The force is strong enough to create a serious risk of being rear-ended by vehicles behind me. This has happened at highway speeds and on local roads, making the vehicle unsafe to operate. If a following driver is unable to react in time, this defect could easily cause a crash, injury, or death. The problem appears related to the vehicle’s automatic emergency braking / Active Brake Assist / forward collision avoidance system and possibly other linked driver-assistance systems. The vehicle has already been serviced on two separate occasions for this exact issue, yet the problem has occurred again. Despite bringing the vehicle in for repair more than once, the defect remains unresolved. Because this dangerous unintended braking continues to happen, I cannot continue to drive the car safely with this issue unresolved. On April 1, 2025, I took the vehicle to Aristocrat Motors in Merriam, Kansas for the car slamming on the brakes and beeping when no one was around. The service center calibrated the augmented reality camera and performed a test drive. The invoice indicates that they were unable to duplicate the braking event during the test drive. They ran codes with SDS and found that the augmented reality camera was not calibrated correctly, so they performed a calibration. On December 31, 2025, I again took the vehicle to Aristocrat Motors in Merriam, Kansa

NHTSA ID

11735812

Incident

May 5, 2026

The contact owns a 2023 Mercedes-Benz C43 AMG. While driving into a parking lot at a very slow speed, the braking system suddenly activated, and the vehicle shut off. After restarting the vehicle, the messages "Rear Axle Malfunction", "Active Braking System Limited" and "Inoperative" were displayed. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure. The failure mileage was 5,600.

NHTSA ID

11572056

Incident

Feb 15, 2024

Mileage

5,600 mi

This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below. In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC (“MBUSA”) is extending the warranty coverage on the Diagnostic Module for Tank Leakage detection (DMTL) in certain Model Year (“MY”) vehicles listed below from the original New Vehicle Limited Warranty of 4 years/50,000 miles to 10 years/120,000 miles (vehicles certified as LEV II) and 15 years/150,000 miles (vehicles certified as LEV III), whichever occurs first, for the following condition: •Under certain circumstances, the DMTL may trigger erroneous Diagnostic Trouble Code (DTC) entries that may result in the illumination of the Check Engine Malfunction Indicator Lamp (‘MIL’).

Complaint Audible "slurping" operating noise from the fuel tank Cause Conditions: • The fuel tank is around half full • The secondary chamber is almost empty. The suction jet pump suctions up small quantities of fuel and air. This results in vibrations and turbulence, which make noises. These noises may sound like slurping. The fuel pump and the drained secondary chamber amplify certain noises which can be loud or shrill. The viscosity of the fuel and the intensity of the fuel pump also impact the noises. • The fuel level is in the area of the saddle overflow in the primary chamber. The fuel mixed with air flows back into the secondary chamber. The noises may therefore be audible for longer • If the primary chamber is no longer in the area of the saddle overflow, the noises should disappear because the secondary chamber no longer receives fuel. • The area of the saddle overflow in the primary chamber is around +/- 2 liters of fuel volume (fuel gauge shows around half full). Remedy • Refill/drain approx. 5 liters of fuel; if the noise is reduced/is no longer present due to this, the circumstance specified above is present Further measures may cause a reduction in noises in the specified area: • In isolated cases, a fuel tank installed under stress may amplify the noises. The installation position of the fuel tank and the contact surfaces on the body-in-white should be checked here. To do so, release the fuel tank and refasten it, see WIS. • Replacement of component parts such as fuel tank/delivery module does not provide a remedy! If a similar noise is heard, but the tank volume is 3/4 or 1/4 and not 1/2 as described above, another circumstance is present

Complaint Crackling and cracking noise from the outer wheel on the front axle when cornering Cause The noise is generated by a micromovement on the contact surface between the rim and the brake disk (wheel bolt group) and may be intensified by potential soiling. The more lightweight rim (AMG forged rim) transmits the noise louder; in the case of cast rims, the noise is generally not perceptible. This is not a technical defect, but rather a complaint concerning comfort. Safe operation of the vehicle is ensured at all times. Remedy Important note: The operations described below do not represent a permanent remedy in every case. The noise may reoccur again after an indefinite period of time; sanding the rims with abrasive media multiple times is not permissible. Only cleaning using the Hazet tool 4960-160 (recommendation) can be performed without any concerns each time the wheel is changed or if the complaint reoccurs. Replacing the parts (rim, wheel bolts, wheel bearings, wheel hub, brake disk) is not expedient in the event of this complaint. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Clean the components of the wheel bolt connection according to the WIS instructions Sand down the rim and brake disk bowl by performing the following steps: • Manually sand rim (old design only) in area of water drain bores (Figure 1; item A), approx. 1.5 cm left and right of water drain bore (Figure 2) Note: Use abrasive paper with grit size 80. The grooving in this area should no longer be visible (sand down approx. 0.1-0.2mm) • Also sand brake disk bowl using emery cloth or abrasive paper with a grain size of 120 • For vehicles equipped with the AMG ceramic brake system (B07), abrasive paper may not be used for cleaning on the brake disk side Note: Do not use any cleaning agent when cleaning on the rim side. Cleaning using abrasive paper with a grain size of 80 will suffice. Do not apply any grease, lubricant or paste after cleaning The brake disk bowl should be "bare metal" in the area of the imprints made by the hole (Figure 3)

Complaint After an "Over the Air" update (OTA), FM or SDARS radio reception is limited; only a few stations are found. Cause The firmware installation was incomplete. Remedy In the A26/17 control unit "MBUX multimedia system" (head unit), use XENTRY to carry out the special process "All Modules"; this will reinstall the firmware completely.

Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to cracking of the microweld between the wheel bearing inner race and the joint housing of the side shaft. Note: The collar nut must always be replaced after being loosened. See also LI33.20-P-078406 Remedy Coat contact surface of side shaft with wheel bearing with Molykote paint. To do this, proceed as follows: 1. Remove side shafts 2. Clean contact surface A (see image file in attachment "Outer joint housing before") before coating with Molykote, using "spirit" (free of dust and grease) 3. Coat contact surface A (see image file in attachment "Outer joint housing after") with Molykote and leave to dry for "one hour" in removed condition 4. Reinstall side shafts Note: Before using the antifriction coating (Molykote), stir it or shake it thoroughly for (at least 1 minute).

Complaint Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the following scenarios: • Flashing without a speed limit ("- -"). • Flashing when current vehicle speed is under speed limit. • Flashing between US speed limit symbol and European speed limit symbol. NOTE: • Verify that the concern falls under one of the attachment videos. If not, then it is outside of the scope of this LI. • This also does not cover "Traffic Sign Inoperative" messages on the instrument cluster. Cause There are two identified reasons for this concern: 1. Country code information stored incorrectly at a particular geographic latitude range. 2. Incorrect reference data when the vehicle is started and a GPS signal is not immediately available. Remedy Do not replace parts. Please open a TIPS case to the Body/Chassis/Entertainment inbox but read the below carefully: • The vehicle must be exhibiting the concern as shown in the attachment videos. • The vehicle DOES NOT need to be at the dealer, nor does it need to be brought into the dealership. • If the geographic location is known, it is very important that it is provided. • Provide any pictures or videos, if available. A new software for the head unit is scheduled for tentative release in Q3 2026.