2018 Mercedes-Benz C 300 4MATIC

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.

Driving the freeway and heard a loud bang noise which was my sunroof. It started cracking the whole thing and just flew away the middle part of glass on freeway.

NHTSA ID

11776110

Incident

Oct 19, 2026

Sunroof causing dangerous pinch conditions. Roof tracks break and cause pinch areas with partial opening of roof

NHTSA ID

11760196

Incident

Aug 24, 2026

I have begun noticing symptoms of the adhesive failing, such as excessive wind noise coming from the front roof area and visible gaps/separation between the panel and the vehicle body. This poses a severe safety risk, as the panel could completely detach while driving and become a high-speed road hazard. No warning lights have appeared. The vehicle and component are available for inspection upon request.

NHTSA ID

11753879

Incident

Jul 25, 2026

2018 Mercedes C300 - a hole rusted through the rear subframe causing structural safety concerns. This car has been routinely washed weekly and the frame should not have rusted through within only 8 years. This also led to a large repair bill.

NHTSA ID

11752562

Incident

Jul 23, 2026

****Please force Merces to recall all VIN's!******* NHTSA ID Number: 23V854000 1) Front glass roof panel came off while driving the car on the freeway. I didn't see or hear anything. When I got out of the car, I saw the entire piece has come off. This has caused my sunroof to malfunction, and it won't close now. I garage my car and barely drive it. I bought it used in Dec. 2021. There was about 46,000 on it in Dec 2021 and now (June 2026) the mileage is 51,000. Yes, the car is available for inspection. 2) I was on the freeway, didn't see it come off. No cars immediately in front or behind me. 3) There have been many complaints that this has happened, but Mercedes won't fix it and just say our VIN's are not part of the recall. Mercedes has not taken responsibility that this has affected more cars than they are admitting to. Mercedes says my VIN is not on their list too. 2018 Mercedes C 300 4Matic Sedan- 4) I will take to a Mercedes Dealership to get an estimate soon. 5) No warning lights or sounds.

NHTSA ID

11743333

Incident

May 19, 2026

Mercedes-benz usa. llc (mbusa) is recalling certain 2014-2020 c-class, cla, gla, s-class. glc, and gle vehicles. please refer to mbusa's recall report for specific vehicle details. the front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair, allowing the front panel to detach from the vehicle., Consequence A detached roof panel can become a roao hazard, increasing the risk of a crash I went to the dealership about this complaint 2 years ago not even knowing about an official recall of this exact problem. I don't drive my car as much because it was an issue that never got fixed. I was never told about a recall. They said there is a whistling and it could fly off (the panel)

NHTSA ID

11739465

Incident

Mar 22, 2024

When I decelerate my brake lights don’t flash to warn the driver behind me that I am potentially slowing down .

NHTSA ID

11733648

Incident

Apr 23, 2026

The contact owns a 2018 Mercedes-Benz C300 4Matic. The contact stated that the front passenger's and driver's side seat belts had failed to retract and return to the stowed position. The contact related the failure to NHTSA Campaign Number: 21V032000 (Seat Belts); however, the VIN was not included. The dealer was notified of the failure and informed the contact that there would be a cost for a diagnostic test. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 59,000.

NHTSA ID

11637991

Incident

Aug 23, 2024

Mileage

59,000 mi

Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process. Cause As part of the on‑going quality monitoring process and associated quality and damaged part appraisals, a high number of ineffective repairs have been discovered. Such ineffective repairs have a negative impact on all those involved. For the customer, it means high costs and long repair times and for the dealer, it may result in the warranty claim being rejected. Remedy General note: IPR is available for: ‑ NAG3 Classic (automatic transmission 725.0) ‑ NAG3 Classic ‑ AMG sport model (AMG 43 and AMG 53 with converter, automatic transmission 725.0) ‑ NAG3 Classic ‑ Hybrid (automatic transmission 725.0) ‑ NAG3 Classic ‑ AMG 63 (automatic transmission 725.0) ‑ NAG3 MOPF ISG2 (automatic transmission 725.1) ‑ NAG3 MOPF Hybrid (automatic transmission 725.1) ‑ NAG3 MOPF AMG sport model (AMG 53/AMG 53e with ISG48V2 & converter /hybrid, automatic transmission 725.1) ‑ NAG3 MOPF AMG 43/63 with engine 139/177 (automatic transmission 725.1) Steps for the Service Advisor: Important: The more information and detail that can be given to the workshop about the complaint, then the more effective the subsequent diagnosis with IPR can be. To this end, a detailed service reception questionnaire has been provided to help the Service Advisor ask the right questions about the complaint. ‑ Ask precise details about the customer complaint and the conditions and context. ‑ Fill out the service reception questionnaire (please see WIS document: OF27.00‑P‑3000‑05A) for customer complaints in detail and forward it to the workshop. Operation steps for the workshop employee: 1. Perform quick test 2. Access the transmission control unit via XENTRY Diagnosis 3. Select "A customer complaint has been received" and carry out all subsequent operation steps (IPR diagnosis path). 4. The IPR repair instructions are displayed, Carry out the IPR repair instructions without performing any further diagnostic or repair steps. ‑ Important: The IPR repair instructions are binding and must be carried out. Differing repairs are possible; such repairs must be documented in XENTRY in free text. Please observe the information regarding the IPR diagnosis process in XENTRY. Conventional diagnosis and subsequent appropriate repairs are only permitted if IPR does not specify any repair instructions. Invoicing for the guided IPR steps: Operation item 27‑0640 and 0.1 hours Notice regarding warranty: The use of IPR in association with warranty claims is mandatory! If the IPR repair instructions are disregarded without justification, the warranty claims may be rejected and/or are subject to debit. IPR will provide a measure to repair the vehicle based on various data sources (EEPROM, fault codes, etc). Please consider the vehicle maintenance record of the vehicle. For warranty and goodwill repairs, the transmission ECU test log and/or IPR test result must be uploaded into Paperless XENTRY Diagnosis (pXD) . If repair is being determined based of oil pan condition pictures of oil pan MUST be provided to warranty as justification. ·Tamper‑proof documentation: The IPR repair instructions are stored in the control unit log. Please file this document in a tamperproof manner ‑ either in digital form or as a hard‑copy printout and also enclose a printout with the damaged part. In this regard, please comply with the country‑specific warranty requirements of the MPC/general distributor.

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 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 Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load, vibrations or jolting sensation may come from the drivetrain. It may be mistaken for a harsh shift. Cause Modified oil quality of the transfer case over time Remedy 1. Check initial quick test for faults in the following control units. N45 or N15/7 ‑ All‑wheel drive (ARS) N127 ‑ 'Drivetrain' (PTCU) control unit Y3/8 ‑ Transmission control for 9‑gear transmission (VGS) N3/10 ‑ Engine electronics for combustion engine If faults are present: Process them as per the guided test in Xentry. If no faults are present: 2. Check the transmission oil level If the oil level is correct: 3. Unplug the connector for the transfer cases control unit and reassess the vehicle on a subsequent test drive If the complaint no longer occurs with the control unit disconnected: 4. Perform an oil change of the transfer case according to WIS specifications ‑ Collect an oil sample of the original fluid 5. Complete all transfer case Tech‑in processes located under VG Control Unit > Adaptations ‑ Resetting the oil service data ‑ Calibration of N15/7 5. Perform road test of vehicle to bring transmission to operating temperature (>60C ) 6. Operate vehicle in full circle with steering at full lock ‑ 5x to the left ‑ 5x to the right Return the vehicle to the client and request they drive the vehicle for at least 200 miles and return if the concern is not resolved. The extended drive will ensure the clutches are properly conditioned with the new oil and should resolve the concern. If this LI has already been applied to the vehicle, please submit a TIPS case to the Powertrain inbox with the following information: ‑ Initial quick test with fault freeze frame data ‑ Initial transmission EEPROM data ‑ VGS and Transfer Case Control Unit Log (N45 or N15/7) ‑ Special Acquisition Data .txt file (Transfer Case Control Unit > Special Procedures > Procedures for support queries to market support > Special Data Acquisition) ‑ Photo of the original oil condition ‑ What color was the fluid drained from the transfer case before the oil change? ‑ Was an oil sample collected, and can you provide a photo of the original fluid? ‑ What color and part number fluid was used during the oil change? ‑ How far was the vehicle driven after?

Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process. Cause As part of the on‑going quality monitoring process and associated quality and damaged part appraisals, a high number of ineffective repairs have been discovered. Such ineffective repairs have a negative impact on all those involved. For the customer, it means high costs and long repair times and for the dealer, it may result in the warranty claim being rejected. Remedy General note: IPR is available for: NAG3 Classic (automatic transmission 725.0) NAG3 ‑ AMG sports models (AMG 43 and AMG 53 with converter) NAG3 ‑ AMG 63 NAG3 ‑ Hybrid NAG3 Facelift (automatic transmission 725.1) NAG3 facelift (725.1) with engine 139/177 (AMG 43/63) Steps for the Service Advisor: Important: The more information and detail that can be given to the workshop about the complaint, then the more effective the subsequent diagnosis with IPR can be. To this end, a detailed service reception questionnaire has been provided to help the Service Advisor ask the right questions about the complaint. ·Ask precise details about the customer complaint and the conditions and context. ·Fill out the service reception questionnaire (please see WIS document: OF27. 00‑P‑3000‑05A) for customer complaints in detail and forward it to the workshop. Operation steps for the workshop employee: Perform quick test ·Access the transmission control unit via XENTRY Diagnosis ·Select "A customer complaint has been received" and carry out all subsequent operation steps (IPR diagnosis path). ·The IPR repair instructions are displayed. Carry out the IPR repair instructions without performing any further diagnostic or repair steps. ·Important: The IPR repair instructions are binding and must be carried out. Differing repairs are possible; such repairs must be documented in XENTRY in free text. Please observe the information regarding the IPR diagnosis process in XENTRY. ·Conventional diagnosis and subsequent appropriate repairs are only permitted if IPR does not specify any repair instructions. ·Invoicing for the guided IPR steps: Operation item 27‑0640 and 0.1 hours !!!!! Notice regarding warranty: !!!!! ·The use of IPR in association with warranty claims is mandatory! ·If the IPR repair instructions are disregarded without justification, the warranty claims may be rejected and/or are subject to debit. IPR will provide a measure to repair the vehicle based on various data sources (EEPROM, fault codes, etc). Please consider the vehicle maintenance record of the vehicle. For warranty and goodwill repairs, the transmission ECU test log and/or IPR test result must be uploaded into Paperless XENTRY Diagnosis (pXD) . If repair is being determined based of oil pan condition pictures of oil pan MUST be provided to warranty as justification. ·Tamper‑proof documentation: The IPR repair instructions are stored in the control unit log. Please file this document in a tamperproof manner ‑ either in digital form or as a hard‑copy printout and also enclose a printout with the damaged part. In this regard, please comply with the country‑specific warranty requirements of the MPC/general distributor.