2018 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 2018 Mercedes-Benz S450. The contact stated while driving at an undisclosed speed, the gear shifter independently shifted into neutral. The contact had to hold down the gear shifter for about 30 seconds before the system was reset. Additionally, the check engine warning light was later illuminated. The vehicle was taken to the dealer where it was diagnosed with transmission valve body failure. The contact was informed that the transmission valve body needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 89,000.

NHTSA ID

11637720

Incident

Dec 22, 2024

Mileage

89,000 mi

I was driving on highway on 7/26 Friday in exit lane when my panoramic sunroof exploded and shattered on me while driving. It sounded like a shogun. Some of the glass came in on me and other part flew out vehicle causing paint damage. I inspected car there was no impact from anything (ie rock, branch etc). It was a clear sunny dry day no vehicles in front that would have kicked up an object no impact whatsoever. I made to my house 3 miles away and there is no impact after inspection i have insurance adjuster coming Monday 7/29. I checked internet and have heard of others stating same experience. I looked at NHTSA site and my car doesn’t look like it was part of a national recall notice. Very frightening situation a more inexperienced driver may have not handled the situation.

NHTSA ID

11604856

Incident

Jul 26, 2024

Steering wheel became extremely stiff to turn and a message that read “steering malfunction increase physical effort” appeared while driving at around 30 mph while in a vacation trip, not only was this extremely unsettling since it happened suddenly but I had to act fast to avoid a collision with other vehicles, once I made it to a safe location I shut the vehicle off and restarted after 15 minutes and it seem drivable again but left me extremely concerned as I am 500 miles away from with no dealerships open to have it looked since is Memorial Day.

NHTSA ID

11524278

Incident

May 28, 2023

The contact owns a 2018 Mercedes-Benz S450. The contact stated while driving at an undisclosed speed, the contact attempted to depress the brake; however, the vehicle failed to decelerate and slow as needed. The contact stated that the brakes failed to work as needed. The contact stated that the “Service Required” message was displayed on the instrument panel. The vehicle was taken to a dealer and was diagnosed with electronic parking brake failure. The manufacture was not notified of the failure. The failure mileage was approximately 40,000.

NHTSA ID

11509829

Incident

Feb 28, 2023

Mileage

40,000 mi

I’m reporting this safety concern and seeking advisement from those more knowledgeable than myself on this issue. Recently, as I attempted to actuate the brake of my vehicle. My right foot was entangled with the brake pedal as I moved it from the acceleration pedal to the brake pedal in observance of a “Stop Sign.” I barely avoided what surely would have been a catastrophic collision with another vehicle. The incident occurred in a split second. The shoe of my right foot was entangled with the lower right corner of the underside of the brake pedal, which has a protruding sharp thin metal edge. The sharp thin metal edge impeded the performance my right leg as it dug into my shoe’s sole edge and the leather upper. In my opinion the sharp thin metal edge of the underside of the brake pedal as described herein is a dangerous and extremely problematic issue. After the recent incident, I am consumed with concern, trepidation and fear when operating the vehicle. During the excitement of the near collision, my wife made an audible gasp, and in the split second I struggled to free my shoe and foot to avoid a potentially fatal crash. I barely freed my foot and shoe in time enough to successfully bring my vehicle to a halt. My wife and I narrowly averted a life changing, potentially deadly accident.

NHTSA ID

11509192

Incident

Feb 18, 2023

TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ S450. WHILE DRIVING 75 MPH WITH THE CRUISE CONTROL ENGAGED, THE AUTOMATIC BRAKING ACTIVATED ON ITS OWN IN TRAFFIC. THE CONTACT HAD TO DEPRESS THE BRAKE PEDAL TO DISENGAGE THE CRUISE CONTROL IN ORDER TO DRIVE SAFELY. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF ALEXANDRIA (200 S PICKETT ST, ALEXANDRIA, VA 22304, (703) 341-2100) TO BE DIAGNOSED, BUT THE FAILURE COULD NOT BE DUPLICATED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 49,826.

NHTSA ID

11217774

Incident

May 22, 2019

Mileage

49,826 mi

THE PRE-COLLISION SAFETY FEATURE GOES OFF WHEN THERE IS NO COLLISION IMMINENT. IT IS FRIGHTENING AND COULD ACTUALLY CAUSE AN ACCIDENT.

NHTSA ID

11053437

Incident

Nov 23, 2017

Mileage

850 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’).

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.

Complaint The customer requests deactivation of the N112/9 HERMES communication module Note: Deactivation of the HERMES control unit (N112/9) is not supported for gray-market vehicles. Cause Before deactivating the HERMES control unit (N112/9), it must be clarified by the legal department of the respective MPC whether and under what conditions deactivation may be carried out. If deactivation is not permissible under applicable law, the HERMES control unit (N112/9) must not be deactivated. Remedy Please inform the customer that, following deactivation, the vehicle will no longer be able to place an automatic emergency call, nor will the customer be able to place a manual emergency call. After deactivation, the Mercedes-Benz Digital Extras will also no longer be available. Please have the attached sample form checked by your market's legal department, adapted to local requirements if necessary, and approved. Furthermore, after informing the customer about the effects of deactivation, please have the workshop complete and sign the approved form together with the customer, and send it to the MPC via a TIPS case for audit-compliant documentation. Furthermore, the workshop must affix a sticker to the emergency call button cover on the overhead control panel and to the emergency call button itself. After affixing, pictures of the overhead control panel need to be attached to the TIPS case for audit-proof documentation. After deactivation, the HERMES control unit (N112/9) is in the "Out of Service" operating status, and the display "SOS NOT READY" appears in the Audio/COMAND system. This display message tells the customer that the emergency call function is not available. In detail, the following steps must be carried out 1. The workshop must inform the customer about the effects of deactivation (see above) 2. Legal review by the MPC Legal department to determine whether deactivation is permissible for the vehicle and provision of a market-specific customer form based on the examples (see "Example - Deactivation communication module HERMES customer declaration English V3.0.pdf") 3. Completion of the market-specific customer form by the workshop and obtaining the customer’s signature 4. Creation of a XSS ticket by the workshop for the MPC with the signed customer form attached 5. Written confirmation of legally reviewed and approved deactivation by the MPC in the TIPS case (see attachment How+to+request+adding+Code+09o+via+XSS+v2.pdf, point 1) 6. Creation of an XSS ticket for documentation of the SA code "09o" (zero nine oh) in the Vehicle Documentation System (see attachment How+to+request+adding+Code+09o+via+XSS+v2.pdf, steps 2–7) 7. Ordering of stickers (part number A9078172900), quantity: 2 8. Affixing of the sticker (part number A9078172900) to the cover of the emergency call button on the overhead control panel (see attachment HERMES-Deactivation_+pictures+of+sticker.png) 9. Affixing of the sticker (part number A9078172900) to the emergency call button on the overhead control panel (see attachment HERMES-Deactivation_+pictures+of+sticker.png) 10. Taking photos of the applied stickers and attaching them to the TIPS case 11. After the XSS ticket has been successfully processed, the communication module must be deactivated using XENTRY: • Connect XENTRY Diagnosis • Access the HERMES control unit (N112/9) • "Adaptation" tab, menu item "Teach-in processes" -> "Deactivation" • Follow the instructions