2021 Mercedes-Benz AMG GLC43

Moisture began collecting inside the left headlight assembly, even though the housing should be sealed. Over time, the condensation increased and the front left turn signal failed. The vehicle displayed warning messages for the turn signal, low beams, Blind Spot Assist, Traffic Sign Assist, and Active Brake Assist. The failed turn signal reduces the vehicle's visibility to other drivers and creates a potential safety hazard. A similar moisture intrusion issue was the subject of NHTSA Recall 22V-261 for certain 2021 Mercedes-Benz GLC vehicles, but this vehicle was not included in that recall despite exhibiting the same symptoms. The vehicle is available for inspection.

NHTSA ID

11754832

Incident

Jul 21, 2026

The engine-driven vacuum pump and turbocharger boost-control vacuum system malfunctioned. The vehicle developed insufficient vacuum to the boost-control system, resulting in a P0299 turbocharger underboost fault and reduced engine power. The vehicle is available for inspection upon request. The vehicle experienced a noticeable loss of peak power and reduced acceleration. Although it did not enter limp mode, unexpected reduced acceleration could create a safety risk while merging onto a highway, passing another vehicle, entering or crossing traffic, or attempting to avoid a collision. An authorized Mercedes-Benz dealership scanned the vehicle, confirmed fault code P0299, and documented that vacuum supplied to the turbocharger boost-control system was too low. The dealership recommended replacing the vacuum pump and retesting the vehicle. The vehicle was inspected and diagnosed by an authorized Mercedes-Benz dealership. Mercedes-Benz USA reviewed the case and the dealership’s diagnosis as part of a goodwill-assistance request, but Mercedes-Benz USA did not physically inspect the vehicle. The vehicle has not been inspected by police or insurance representatives. The check-engine light illuminated, and the vehicle stored a P0299 turbocharger underboost fault. I also noticed reduced peak engine power and weaker acceleration. The vehicle did not enter limp mode. These symptoms first appeared at approximately 42,000 miles on or around June of 2026. Mercedes-Benz has issued an extended warranty for vacuum-pump failures on certain M157-powered vehicles that identifies the same vacuum-pump part number used in my M276-powered GLC 43 and describes similar symptoms, including low boost, a check-engine light, and P0299. Although my vehicle is not currently included in that extension, the use of the identical component and substantially similar failure raises concern that the affected population may extend beyond the listed M157 models.

NHTSA ID

11747935

Incident

Jun 10, 2026

At just 30,000 miles — less than half the mileage at which these failures are typically reported — my GLC 43 was found to have active oil leaks in multiple locations: 1. Front engine covers — oil is seeping from both the front cover gasket area and migrating downward along the engine block. The dealer recommends a full reseal of the front covers at a quoted cost of $1,944. 2. Radial shaft sealing ring of the front axle gear — is actively seeping gear oil, with a quoted repair cost of $1,718. My concern is not limited to cost. Oil migrating from the front cover area toward the lower engine, accessory belt, and turbocharger assembly creates a documented fire risk. The turbocharged M276 engine operates at extremely high surface temperatures in the areas where this oil is accumulating. I will be candid: I have genuine concern about operating this vehicle until these repairs are completed, and I am troubled that a safety-relevant failure of this nature is occurring at such low mileage on a vehicle in this price class.

NHTSA ID

11742742

Incident

Apr 6, 2026

2021 Mercedes GLC 43 headlight is inoperable. Same as reported in campaign 22V261000: "Headlight failure can decrease visibility for both the driver and surrounding traffic, increasing the risk of a crash." Although our car was produced before the dates reported in campaign 22V261000, I believe this is the same defect and the recall should apply to all MY 2021 cars as this is a serious safety issue. The dealer will not repair under warranty.

NHTSA ID

11689974

Incident

Sep 25, 2025

Panoramic sunroof exploded while driving.

NHTSA ID

11521032

Incident

May 8, 2023

The contact owns a 2021 Mercedes-Benz GLC43 equipped with Continental Tires, Tire Line: Sport Contact, Tire Size: 255/40/ZR21, DOT Number: AFHDD76M. The contact stated that on several occasions while driving at approximately 30 MPH and at low speeds on wet pavement, the vehicle started to shake, and a loud abnormal noise was heard in all four tires. No warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the tires needed to be replaced; however, tires were not replaced. The manufacturer was notified of the failure and the contact was advised to call the NHTSA Hotline. The failure mileage was approximately 10,000.

NHTSA ID

11504702

Incident

Mar 31, 2022

Mileage

10,000 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’).

Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class (205, 463, 253, 190 & 222 platforms) vehicles, the engine control unit software does not correspond to current production specifications. It is therefore possible that on-board diagnostics and/or exhaust gas emissions requirements may not be fulfilled.

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)

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 Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/ maneuvering. Sound file attached for comparison. MUST match noise for proper diagnosis. NOTE: Steering functionality is not affected. Cause Contact area between wheel bearing and steering knuckle. See also: LI35.30-P-058566 (Throttle Lift-Off Noise - Rear) LI33.30-P-056665 (Throttle Lift-Off Noise - Front) LI40.10-P-059248 (Wheel cracking noise when cornering) Remedy 1. Perform Operation A and evaluate by testing vehicle. 2. If noise is still present after re-testing: • If 192/232 chassis, verify FIN is in the listed range below in "Operation B" and perform. • If not 192/232 chassis or vehicle is a 192/232 not in the listed FIN range, additional verifications of where the noise is coming from are needed. Use multiple channel NVH method to narrow down location. Verify the LI's listed above were completed or if there are other similar noises associated with the chassis (Example: 192/232 also has under panel noises and an associated LI). Operation A: 1. Clean contact surfaces of wheel bearing and steering knuckle with brake cleaner as seen in the attached pictures. NOTE: The front area of the wheel bearing and the seals must not come into contact with the cleaner, otherwise, the sealing rings will be damaged. 2. Clean threads of wheel bearing mounting. 3. Thinly coat contact surfaces of wheel bearing, steering knuckle, and axle mating face with Molykote (annular joint grease). See the attached steering knuckle and wheel hub pictures for reference. NOTE: Axle mating face greasing is also covered in LI35.30-P-058566 and LI33.30-P-056665. Operation B (Only applies to 192 and 232 in listed FIN range): Only affects vehicles up to FIN end number: • Model series 192: xxx xxx xx 002 876 • Model series 232: xxx xxx xx 022 312 1. Replace steering knuckle. 2. Wheel bearings do not need to be replaced.

Complaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/ maneuvering. Sound file attached for comparison. MUST match noise for proper diagnosis. NOTE: Steering functionality is not affected. Cause Contact area between wheel bearing and steering knuckle. See also: LI35.30-P-058566 (Throttle Lift-Off Noise - Rear) LI33.30-P-056665 (Throttle Lift-Off Noise - Front) LI40.10-P-059248 (Wheel cracking noise when cornering) Remedy 1. Perform Operation A and evaluate by testing vehicle. 2. If noise is still present after re-testing: • If 192/232 chassis, verify FIN is in the listed range below in "Operation B" and perform. • If not 192/232 chassis or vehicle is a 192/232 not in the listed FIN range, additional verifications of where the noise is coming from are needed. Use multiple channel NVH method to narrow down location. Verify the LI's listed above were completed or if there are other similar noises associated with the chassis (Example: 192/232 also has under panel noises and an associated LI). Operation A: 1. Clean contact surfaces of wheel bearing and steering knuckle with brake cleaner (see areas marked blue in pictures "2.jpg" and "3.jpg"). NOTE: The front area of the wheel bearing and the seals must not come into contact with the cleaner, otherwise, the sealing rings will be damaged. 2. Clean threads of wheel bearing mounting. 3. Thinly coat contact surfaces of wheel bearing, steering knuckle, and axle mating face with Molykote (annular joint grease) (see areas marked blue in pictures "2.jpg" and "3.jpg"). NOTE: Axle mating face greasing is also covered in LI35.30-P-058566 and LI33.30-P-056665. Operation B (Only applies to 192 and 232 in listed FIN range): Only affects vehicles up to FIN end number: • Model series 192: xxx xxx xx 002 876 • Model series 232: xxx xxx xx 022 312 1. Replace steering knuckle. 2. Wheel bearings do not need to be replaced.