2016 Mercedes-Benz C 300

From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited. The rapid burning can cause the inflator to rupture during deployment, potentially causing serious or even fatal injury to vehicle occupants. See 2016 Blomquist Report at www.nhtsa.gov/sites/nhtsa.gov/files/documents/expert_report-hrblomquist.pdf.Consequently, all frontal inflators using propellant 2004 that do not contain a "desiccant" (a substance that traps and holds moisture) in US vehicles are under recall. These "non-desiccated" inflators either have been or are required to be replaced.In some cases, the remedy part for these recalled inflators was, or will be, an inflator using either propellant 2004 or 2004L that does contain a desiccant. None of these "desiccated" remedy parts (which were installed in older model year vehicles) are currently under recall for a degradation concern. Certain subsets of desiccated PSAN inflators using propellant 2004 for use as original equipment, however, have been recalled for a degradation concern. All Takata inflators produced with propellant 2004L contain desiccant, and none of these desiccated inflators using propellant 2004L are under recall for a degradation concern. There have been no reported field ruptures in any non-recalled desiccated PSAN inflators.It is understood that desiccants fully saturate at some threshold, at which point any additional moisture will not be captured. This means the degradation process observed in non-desiccated inflators using propellant 2004 may also occur in non-recalled desiccated inflators using propellant 2004, assuming additional moisture enters the inflator and high temperature cycling occurs. Based on available information, desiccant saturation can occur within the first five years in the worst environments, and the time required for full saturation is affected by multiple factors. While no present safety risk has been identified, further work is needed to evaluate the future risk of non-recalled desiccated inflators using propellant 2004.Three entities -- Takata (now known as TK Global), the Independent Testing Coalition, and Exponent -- have been studying the long-term behavior of Takata desiccated PSAN inflators using propellant 2004L (as well as 2004) in the presence of moisture and temperature cycling. The research efforts, which include development of predictive modeling techniques and field sample analysis, are ongoing. To date, none of the researchers have identified field evidence showing that propellant 2004L is undergoing a degradation process that leads to aggressive deployment and potential rupture. However, the time in service of such inflators remains short compared to that of the inflators using propellant 2004. Further study is needed to assess the long-term safety of desiccated inflators using propellant 2004L.The Office of Defects Investigation is opening this investigation to examine whether a safety defect related to propellant degradation exists in non-recalled desiccated PSAN frontal inflators manufactured by Takata. This investigation will require extensive information on Takata production processes and surveys of inflators in the field. Lists of recall actions that may have used desiccated PSAN inflators as remedy parts, as well as the makes and models originally manufactured with them, is available with the downloadable version of this document (see nhtsa.gov/recalls?nhtsaId=EA21002 -- note this information is subject to change/revision as the investigation proceeds). This investigation does not supersede EA15-001, which remains open.

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

Premature corrosion of rear subframe. See attached letter for further details.

NHTSA ID

11776450

Incident

Oct 21, 2026

Hi, in the Fall of 2025 my 2016 Mercedes Benz C300 4 Matic, started giving off smelly fumes while my car was idling/ warming up. I registered a complaint with the Corporate Mercedes Benz Office USA, LLC in April 2026 @ 800-367-6372, after the dealership would not correct the issue free of charge. 1. Hose Clamp Replacement problems. 2. The raw fuel leakage produces strong gasoline odors inside the cabin- via the air filter, risk of car stalling and the smell could be leathal. 3. The problem was confirmed in a lawsuit. 4. The dealership would not repair the issue. 5. There were no warning lamps or messages on the dash board, the only essential issue were the smells, fumes, odors and lawsuit.

NHTSA ID

11774091

Incident

Oct 15, 2025

Vehicle: 2016 Mercedes-Benz C300, VIN [XXX], approximately 52014 miles. Purchased Certified Pre-Owned in 2017. All maintenance performed at authorized Mercedes-Benz dealerships. On XXX, during a routine B-Service at Mercedes-Benz of Easton ([XXX]), the technician found that the rear subframe (rear axle carrier) was rusted and perforated. The corroded area is located directly above the rear control arm. The technician stated on a recorded inspection video that the corrosion would continue to spread around that area until the control arm disconnects, and described it as a safety hazard. He recommended replacement of the part. Photos and video (technician shared video link - [XXX]) were taken during the inspection and are available. I was not notified of any corrosion in this area during previous dealer services, and the vehicle showed no symptoms that I noticed before this inspection. I am concerned that a structural suspension mounting component has corroded through on a vehicle of this age, and that if the control arm separates from the subframe, it could cause loss of control. I am reporting this so that NHTSA can determine whether it is a wider problem on this model. No crash, injury, or fire has occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11773422

Incident

Oct 24, 2026

Rear sub frame has rusted through and according to repair shop cannot be safely driven until repaired. Mercedes has granted extended warranty for sub frame rust through for the C300 up to model year 2015 so this is a known problem. My car is a 2016 and Mercedes will not offer the extended warranty.

NHTSA ID

11771705

Incident

Oct 9, 2026

Failed state safety inspection due to a severely corroded and rotted rear subframe, creating an immediate driving hazard.

NHTSA ID

11769345

Incident

Oct 5, 2026

The contact owns a 2016 Mercedes-Benz C 300. The contact stated that while performing maintenance on the vehicle with the dealer, it was discovered that the rear subframe was severely rusted and perforated. The contact associated the failure with Technical Service Bulletin: MC-10232321-0001; extended warranty, but vehicle was not included. The manufacturer was contacted by phone and made aware of the failure. The failure mileage was approximately 84,616.

NHTSA ID

11769311

Incident

Sep 2, 2026

Mileage

84,616 mi

Vehicle has prematurely rusted subframe. It is a know manufacturer defect, for which the manufacturer is covering repair cost for owners of the preceding model, but refuses to acknowledge responsibility on this model. (W204 model covered — W205 Mercedes (only offered $500.00 on a repair they value at over $6,000.00.))

NHTSA ID

11764059

Incident

Aug 5, 2026

NHTSA Safety Complaint – 2016 Mercedes-Benz C300 Vehicle: 2016 Mercedes-Benz C300 | Mileage: 74,662 miles What Happened I’m filing this complaint because my 2016 Mercedes-Benz C300 suffered a sudden, complete engine failure at 74,662 miles, and I believe it’s a safety risk that deserves investigation. I’ve owned this car since 2016 and followed every recommended service interval. All available warranties were purchased and maintained. The car showed absolutely no signs of trouble before this happened. Last week before filing, I was driving normally when the check engine light came on without any prior warning — no oil pressure light, no temperature alert, nothing else. Within minutes, the engine shut off completely. The car rolled to a stop and I noticed oil leaking from the front of the engine. It was towed to an authorized Mercedes-Benz dealership, where they confirmed the engine suffered a catastrophic internal failure and needs to be fully replaced. Why This Is a Safety Concern No advance warning. The check engine light appeared only minutes before the engine died. That’s not enough time to safely exit a highway or busy road. A sudden total engine failure at speed affects steering, braking assist, and reaction time — it could easily cause a serious accident. Engine failure at 74,662 miles is not normal. A complete engine failure on a well-maintained luxury vehicle at under 75,000 miles strongly suggests a manufacturing defect or design flaw, possibly affecting other vehicles of the same model year. Oil leak at engine front. The leak observed at failure likely points to a specific component or seal failure. If this is a design weakness, other 2016 C300 owners may be at risk without knowing it. What I’m Requesting 1.Open an investigation into the 2016 Mercedes-Benz C300 for sudden engine failure and inadequate warning systems. 2.Determine whether other owners have reported similar incidents. 3.Evaluate whether a safety recall is warranted.

NHTSA ID

11739458

Incident

May 11, 2026

Complaint Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE: Although the symptom is similar to a tire or wheel vibration, it is usually readily noticeable that it is distinctly different if it happens at all times or only while braking. Cause Although the cause of the vibration is most likely due to excessive lateral runout on the rotor or hub/wheel bearing, the system as a whole needs to be checked for other possible contributors. 1. Prior collision damage. 2. Excessive vehicle sitting times without rotating components. 3. Wheel bearing/hub lateral runout. 4. Wheel mating interface has been overtightened (did not follow WIS torque procedures). 5. Mating interfaces have been excessively modified (painted, gouged, bent, etc...). Remedy Read through the entire attached worksheet prior to performing. After performing, please review the final page and perform work accordingly. NOTE: This document is not pre‑authorization or otherwise dealing with warranty. This is intended for diagnostic purposes only. If there are any questions on how to proceed OR The work sheet has been performed and the vehicle has returned with the same concern. Please perform the measurements as seen in the worksheet again and open a TIPS case to the Body, Chassis, and Entertainment team.

Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment. Note: Please refer to this document in the warranty claim and, once diagnosis is completed, select the damage code depending on the component part that is causing the issue. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10‑P‑067691. Information: In this case, do not use a damage code for the speakers in the warranty claim!

Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering (see attachment). Complaint does not impact the ability to safely steer or control the vehicle. Cause Ball screw drive (KGT) of electric steering damaged by: 1. External force due to: ‑ Hitting the curb/posts with the front wheels. ‑ Driving over obstacles (e.g. pothole/ threshold/ speed bump/ gully) at an inappropriate speed. 2. Corrosion/ water ingress through a damaged boot (see attachment). ‑ Cracks (1) ‑ High pressure cleaner (2) ‑ Animal bite (3) See various examples listed in the attachments for examples of outside influence. Remedy Remove boot clamps closest to steering gear housing on both left and right (as seen in "Steering Rack Boot Clamp Location"). Pull back boot and inspect for rust, broken end stops, water, or any other anomalies. Replace electric steering. Note: Steering gears replaced due to outside influence or damage must not be claimed under warranty!

Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th generation, the vehicle key can be recoded so that the tailgate no longer opens as a result of a long press on the button, but by double‑clicking on the button instead. This reduces the likelihood of the button being activated accidentally or unintentionally. The recoding can be carried out as follows: 1. Add SA Code O19 into VeDoc (O for Oscar, not "zero") • an XSS ticket may be necessary to add the SA code 2. Perform SCN coding of EIS N73 control unit 3. Deactivate the vehicle key (a successful deactivation is indicated by the LED lighting up 2x briefly and then 1x for a long period). 4. Place the vehicle key in the storage compartment on the key symbol and turn on the ignition. IMPORTANT: all other vehicle keys must be outside the recognition range of the vehicle when doing this! Perform steps 3 and 4 successively for all vehicle keys. Notes: 6th, 7th and 8th generation keys can be deactivated as follows: Up to modification year 22/1 by double clicking the "Lock button" As of modification year 22/1, by press and holding the “Lock button", then double‑click the “Unlock button" at the same time. On model series 167, the storage compartment with the key symbol is located in the armrest. The SCN coding from the EZS is only transferred correctly to the vehicle key under the following conditions: Only one vehicle key is located in the vehicle, this key has been deactivated and it is positioned on the marking in the storage compartment for the data transfer. The costs for this adaptation are to be borne by the customer. For the newer BR 174, 178, 244, 248, 520, and 540, a software update must be initiated, as there is no way to perform SCN coding.

Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause Various root causes Remedy See attached diagnostic guide.

Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment. Information: Please refer to this document in the warranty claim and, after completing diagnosis, select the damage code corresponding to the component part that caused the problem. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10-P-067691. Information: In this case, do not use a damage code for the speakers in the warranty claim!