2019 Mercedes-Benz S 450

On January 8, 2021, after ongoing review with Mercedes Benz, the National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation (ODI) opened PE21-001 to assess allegations of front roof panel detachments while driving at highway speeds in certain 2015 Mercedes-Benz (Mercedes) C-Class vehicles.The subject front roof panel is a stationary panel composed of polycarbonate and is attached to the vehicle via adhesive at the time of manufacture. The panel is found on subject vehicles equipped with panoramic sunroofs. Over time, the subject panels may exhibit cosmetic degradation leading to replacement of the panel, a procedure which entails: removal of the old panel and adhesive, site preparation, and installation of a replacement panel with new adhesive.The consumer complaints that prompted the opening of PE21-001 all described detachments of front roof panels that had been replaced after the vehicle was put into service.Mercedes' internal investigation identified a broader scope of affected vehicles (2014-2020 CLA, GLA, C, S, GLC, and GLE class) and found the following potential service procedure- related causes of front roof panel detachments:- Improper surface pretreatments such as the use of the wrong primer or cleaner or scoring of the surface; or - Use of the incorrect adhesive.These conditions lead to a front roof panel bond that, even if sound at the time of repair, cannot maintain its strength over time and environmental exposure.Mercedes updated its service and parts ordering systems to reinforce the proper use of specified kits and procedures via webinars, shop foreman meetings, and explicit reference to the risks incurred by diverging from the repair procedures. Mercedes is also furnishing parts ordering assistance, and will hold dealerships accountable for improper repairs.ODI's analysis of the ten complaints it has received from the public (VOQ's) and MBUSA's complaint data submitted in response to the information request letter for PE21-001 identified a total of 57 non-duplicative reports alleging incidents in which the front roof panel detached from the vehicle while in motion. Included within the 57 reports are incidents where consumers state the panel detached ...and flew off into traffic.On March 19, 2021, Mercedes notified NHTSA that it would recall subject vehicles with front roof panels known to have been replaced after the original sale of the vehicle. In total, the recall (designated as Recall 21V197) covers 15,099 vehicles that were ever registered in the United States. Based on Recall 21V197 and the remedy implemented by Mercedes, further investigation does not appear to be warranted at this time.Accordingly, this investigation is closed.The ODI complaints cited above can be viewed at www.nhtsa.gov under the following ODI identification numbers: 11376425, 11352686, 11351629, 11349158, 11341541, 11337594, 11324100, 11311591, 11222127, 11404183

The contact owns a 2019 Mercedes-Benz S450. The contact received notification of NTHSA Campaign Number: 26V216000 (Power Train); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experience a failure.

NHTSA ID

11744748

Incident

Jun 17, 2026

The car is out of control! It first began a couple of weeks ago when (1) the side view mirrors no longer closed automatically 2) Next, while I was driving, the car yesterday, the seat belt suddenly tightened as the car prepared for a sudden impact (which there was none).3) Today, the car refused to stop when I backed it out of the garage. It hit a tree behind us and the car has a rear dint! I am now fearful of driving this car. It needs major servicing or something!!! I have had it towed in to my local Mercedes-Benz dealer.

NHTSA ID

11688276

Incident

Sep 16, 2025

A PORTION OF THE GLASS ROOF SHATTERED WHILE I WAS DRIVING DOWN A MULTI LANE HIGHWAY GOING SLOWER THAN THE SPEED LIMIT SINCE IT WAS EVENING COMMUTER TIME. THE ROOF HAS THREE GLASS SECTIONS. THE FORWARD MOST SECTION OF THE GLASS ROOF IS WHAT SHATTERED.

NHTSA ID

11280685

Incident

Nov 15, 2019

Mileage

3,700 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.

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.

Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, July 9, 2026. After July 9th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.