2023 Mercedes-Benz AMG C43

My vehicle developed a coolant warning during normal road use. I had not experienced any known collision, crash, or unusual impact. I brought the vehicle to an authorized Mercedes-Benz dealer for inspection. The dealer diagnosed the problem as: “Front low-temperature cooler replacement – impact damage causing leak.” The repair estimate was approximately $2,385. The failed component is the front low-temperature cooler located directly behind the lower front grille. Based on the location and design, the cooler appears to have limited protection from ordinary road debris. The dealer believes that external impact caused the cooler to leak. I am concerned that this may represent a design or durability issue because a critical cooling-system component appears vulnerable to relatively small road debris during normal driving. A puncture or leak in this component can result in coolant loss, warning messages, overheating, reduced vehicle operation, or potentially loss of propulsion if the vehicle continues to be driven before the driver realizes the severity of the leak. This is a significant safety concern because the failure can occur suddenly during normal highway or road use without a collision. A driver may be forced to stop unexpectedly or may continue driving with insufficient coolant, which could create a risk to the driver and other road users. I believe Mercedes-Benz should review whether the front low-temperature cooler has adequate protection from normal road debris and whether additional protective screening, grille protection, or a revised component design is needed. The issue has been confirmed by an authorized Mercedes-Benz dealer. The vehicle and damaged component should be available for inspection if requested. I am requesting that NHTSA review whether similar complaints exist and whether this condition may represent a broader safety-related design concern.

NHTSA ID

11766731

Incident

Sep 23, 2026

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

Complaint Diverse functional limitations in the vehicle in combination with various warning and fault messages in the instrument cluster display. Cause Communication timeouts mean that communication errors may occur in the on‑board electrical system, which can result in various fault messages being displayed in the instrument cluster. This could be down to delayed feedback from the drivetrain control unit (N127) (CPC) to other control units networked to the CAN bus. Information: Only valid for vehicles through production period 10/2025. Not valid for vehicles with control unit CDCC (N125, central controller charging and driving) • It may not be possible to attribute any communication errors stored in the control units on the CAN bus to a specific cause • In rare instances, there may be a brief activation of the yellow warning lamp for engine diagnosis or there may be a sporadic delay with the start enable. • There may not be any specific fault codes present that indicate a specific component. Example image: Fault messages in instrument cluster: The reason for this could be down to delayed feedback from the control unit CPC3 to other control units networked on the CAN bus. Remedy Do not replace any components!!! ******************************************************************************************************* 1. Connect charger (see AR54.10‑P‑1127WT). Note: An adequate voltage from the on‑board electrical system battery must be guaranteed for the entire duration of the work procedure. Otherwise, the control units could be damaged if an undervoltage occurs. Information: Observe the operating instructions of the charger. Information: Use the charger to ensure an adequate voltage (at least 12.5 V) from the on‑board electrical system battery. ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑ 2. Connect diagnostic system (see AD00.00‑P‑2000‑06FR). Note: Always use the latest XENTRY Diagnostics software release. Information: Strict compliance with the operation steps in XENTRY Diagnostics is absolutely essential. ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑ 3. Select control unit N127 (CPC) via the direct link using XENTRY Diagnosis. Information: To do so, select the following menu items: Control units view → Drive systems → N127 ‑ "Drivetrain" control unit (CPC) ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑ 4. Update software for control unit N127 (CPC) (see AR54.21‑P‑0014‑01Y). Info: To do so, select the following menu items: Adaptations → Control unit update → Update control unit software. Information: You are then automatically guided through the steps "Update of control unit software" and "SCN coding". Always observe the following operation steps at all times ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑ 5. Disconnect diagnostic device from vehicle (see AD00.00‑P‑2000‑06FR). ‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑ 6. Disconnect charger from vehicle (see AR54.10‑P‑1127WT).

Complaint Wheezing noises/squeaking noises from the front shock absorbers when passing over surface undulations and rough road. Noise MUST match those heard in the attached videos. Cause • Wheezing noises: Flow noises of the damper oil • Squeaking noises: From the mechanical rubber valve in the dividing piston Remedy In case of complaints, the front shock absorbers must be replaced. If shocks have been replaced and noise persists, please open a TIPS case to the Body, Chassis, Entertainment inbox.

Complaint Wheezing noises/squeaking noises from the front shock absorbers when passing over surface undulations and rough road. Noise MUST match those heard in the attached videos. Cause • Wheezing noises: Flow noises of the damper oil • Squeaking noises: From the mechanical rubber valve in the dividing piston Remedy In case of complaints, the front shock absorbers must be replaced. If shocks have been replaced and noise persists, please open a TIPS case to the Body, Chassis, Entertainment inbox.

Issue A software update will be performed that provides enhancements to the robustness and system stability of the communication module. The update is free of charge and runs in the background, which takes about 8 minutes to install. During this time, the vehicle can be driven without any restrictions, and the new software will be active with the next ignition cycle. Remedy MBUSA will conduct an OTA service campaign. Remote software updates are automatically downloaded and installed in the customer’s vehicle free of charge and do not require a dealer visit.

Complaint Slight creaking noises when steering. Cause Noises may come from one or more sleeves of the horn contact plate. Remedy Remove the horn contact plate and check the sleeves for noise; see attached video. If necessary, apply lubricant to the sleeves.

Complaint CEL illuminates and/or AC does not blow cold. Cause Potentially relevance to hardware and/or software Remedy Scenario 1: 1. If the AC does not blow cold air, replace compressor (if compressor's index and part number Figure 1 match against Table 1). a. If the compressor does not fall within Table 1, please open a TIPS case. b. Flush procedure must be followed as per WIS. Scenario 2: 1. If AC does blow cold. a. Follow the following procedure: i. Have the air conditioning system recharged. ii. Clear the fault codes afterward. iii. Let the vehicle stand for 8 hours (OBD reset condition). iv. Check whether the fault is still present. b. Open TIPS case with your findings and answers the following questions, send to the HV/LV inbox. i. When exactly did the MIL appeared (immediately at start‑up or while driving). ii. What was the ambient temperature, any special driving maneuvers, and whether the vehicle had just come out of a climate‑controlled garage.