80 of the
669 complaints filed about the Mercedes Benz C 300
are about the electrical system —
12% of everything owners reported.
The worst model year for it is 2017.
While I am driving my car it will make a loud crackling sound then my screens go black and warning sounds go off! This is not normal and I read there are recalls but when I entered my vin# nothing came up. Not to mention since I bought the car last February, I have had nothing but issues with my AC turning off which that I have taken to the dealership with video proof and told it was a software update which did not fix the issue. i am paying way too much money for a newer vehicle and having more issues than my 2015 Mercedes Cla 250.
NHTSA complaint #11749373 — an unverified report by a vehicle owner.
Throttle body and accelerator pedal position sensors failed. Component is available for inspection upon request. Independent service center confirmed failure on 1/3/2026 with 6 stored fault codes: P2101, P0122, P0222, P0123, P0223, P2135. Vehicle shuts off while driving without warning at various speeds. Loss of power steering and power brakes occurs when engine stalls, creating immediate risk of crash, injury or death to occupants and other drivers. Manufacturer customer service confirmed in writing 4 times that engine shutting off while driving is a safety issue and that these exact codes match Service Campaign 2022090005. On 1/7/2026, manufacturer denied campaign applies to this vehicle and refused no-charge dealer inspection, demanding customer pay diagnostic fees to confirm defect they already documented. Vehicle has not been inspected by manufacturer or dealer because manufacturer refuses free inspection. Check engine light illuminated prior to stall events. Manufacturer has actual knowledge of safety defect under 49 U.S.C. 30118 and is creating financial barrier to repair of defect covered by their own service campaign. Request NHTSA investigation and order manufacturer to repair under Service Campaign 2022090005 at no charge.
NHTSA complaint #11747712 — an unverified report by a vehicle owner.
The contact owns a 2017 Mercedes-Benz C300. While driving at approximately 15 mph, the contact observed smoke emanating from under the hood. The vehicle was driven to her work location and parked. Upon exiting the vehicle and opening the hood, she observed orange flames coming from the engine compartment. A parking attendant extinguished the fire, and a police and/or fire report was filed. The vehicle was towed to a dealer and diagnosed with a fuel line leak that caused the engine harness to come apart. The leaking fuel hose from the high-pressure fuel pump caused damage to the high-pressure pump, engine harness, vacuum transducer, and coolant feed line from the thermostat to the firewall. The following components needed replacement: high-pressure fuel pump, rubber fuel hose, engine harness, pressure transducer, and intake manifold. The vehicle was repaired. Five months later, the contact experienced another failure she believes was associated with the engine fire. While parked and attempting to start the vehicle, it did not start. The vehicle was towed to a dealer and diagnosed with a faulty starter that needed replacement. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 65,422.
NHTSA complaint #11738037 — an unverified report by a vehicle owner.
Vehicle has ongoing and recurring electrical and engine-related defects that affect safe operation. The primary systems involved are the electrical system, engine ignition system, and powertrain. The vehicle is available for inspection upon request. Prior service records show issues beginning in 2020 involving repeated electronic system failures requiring multiple repairs and component replacements. Since purchasing the vehicle in April 2023, the vehicle has developed more serious failures, including: – September 2024: Check engine light with loss of power and inability to exceed safe driving speeds – October 2024: Engine misfiring due to ignition coil failure requiring replacement of ignition components – September 2025: Additional ignition coil electrical fault (code P0353) The problem has been reproduced and confirmed through dealership service inspections and diagnostic reports. Warning indicators, including the check engine light, appeared prior to failure events. These defects create a safety risk due to potential loss of power, engine failure, and unreliable vehicle operation while driving, which could increase the risk of an accident. The issues have required multiple repairs without permanent resolution and appear to be ongoing and worsening over time.
NHTSA complaint #11733212 — an unverified report by a vehicle owner.
After driving the 2025 c300 sedan and leaving it parked for an hour or two, I come back to the car and turn it on. Neither the central screen or drivers screen were operable. The engine, interior lighting, sounds, and other systems were working however all the screens were completely dead. The car had no speedometer, gear selection, park brake, A/C control, or any function. This is the second time it has happened first on 02/12/2026 and then today on 03/17/2026. After locking the car and leaving it alone for an hour, functions restart normally. This is unacceptable and has already happened twice. The car is undrivable as no speedometer, gear, parking/etc is display. Nothing is display as the car has only two displays. The car is running the latest version of MBUX 3.3 and is up to date via OTA software updates.
NHTSA complaint #11725129 — an unverified report by a vehicle owner.
Odometer Fraud. The contact purchased a 2019 Mercedes-Benz C300. The contact stated that after purchasing the vehicle, it was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. The contact stated that at the time of purchase, the odometer reading was approximately 54,000 miles. At the time of registration, the mileage was approximately 54,000 miles, and the same mileage was also reflected on the Carfax report. The contact stated that the mileage discrepancy was later discovered through a public report with the Federal Trade Commission (FTC); however, the mileage was not provided. The contact stated that the mileage discrepancy occurred after two OTA’s were performed on the vehicle. The contact stated that during the OTA’s on the vehicle, the mileage was changed. The contact stated that several documents with the mileage discrepancies were listed with the FTC. The contact also reported the discrepancy to the Department of Motor Vehicles.
NHTSA complaint #11716768 — an unverified report by a vehicle owner.
points: ⸻ While driving, the vehicle displays the warning “Active Brake Assist Functions Limited – See Operator’s Manual.” The message appears during normal driving and does not go away. This warning indicates that the automatic emergency braking / Active Brake Assist system is limited or disabled, reducing a critical safety feature designed to help prevent or mitigate collisions. This creates a safety risk because the vehicle may not automatically brake in an emergency situation. The warning appeared suddenly while driving, with no visible obstructions, weather conditions, or damage to sensors. Restarting the vehicle does not consistently clear the message. The issue has not yet been inspected by a dealer or repair facility. The cause of the malfunction is UNKNOWN, and the vehicle is available for inspection.
NHTSA complaint #11710171 — an unverified report by a vehicle owner.
While driving at approximately 65 mph on the I-405 freeway in Irvine, CA during rainy conditions, my 2019 Mercedes-Benz C300 suddenly and completely lost acceleration without warning. At the same moment, a Check Engine Light illuminated on the dash. I was forced to coast across all lanes and stop in the emergency shoulder in a very unsafe area with high-speed traffic passing close by in low visibility rainy conditions. Multiple vehicles nearly struck us, including one that had to emergency brake directly behind my car in the shoulder. I contacted AAA and the vehicle had to be towed because it was not safe or driveable. My girlfriend was also in the car and both of us experienced significant fear and distress during and after the incident. My mechanic retrieved fault code P019185 and stated this is a known software problem with the engine control unit that requires a Mercedes software update and reset of mixture adaptations per a manufacturer LI/service document. This means the manufacturer appears aware of the defect and the required software fix, yet I received no recall notice or safety warning. A sudden total loss of engine power at highway speeds creates an extreme crash risk and life-threatening danger to the driver, passengers, and surrounding traffic. There have been other serious drivability issues with this vehicle in the past (misfires, coolant pipe failure, etc.), but this incident was the most dangerous. I am reporting this because this defect appears safety-related and could easily cause a fatality if it happens to someone else at freeway speeds. Diagnostic Note from official Mercedes-Benz Fletcher Jones of Newport Beach Mechanic: “FAULT CODE P019185, WILL START WITH PERFORMING THE SOFTWARE UPDATE OF ME CONTROL UNIT, RESET THE MIXTURE ADAPTIONS PER LI DOCUMENT AND RECHECK.” Tow Provider: AAA — tow confirmation available if needed.
NHTSA complaint #11708992 — an unverified report by a vehicle owner.
I am reporting a serious vehicle safety hazard caused by improper and unsafe repair work performed by USA Platinum Motor, located at 1221 California Lane #126B, Arlington, TX. I brought my 2017 Mercedes-Benz C300 in for a cold start rattle with no warning lights or prior issues. The shop diagnosed a loose timing chain and I authorized the repair. After the repairs, the vehicle was returned with critical safety defects, including a loose fuel pump, unsecured fuel line, missing bolts, and improperly reassembled engine components. Shortly after pickup, the car experienced loss of acceleration on the interstate, a strong odor of fuel, and a sudden loss of power, creating a dangerous and life-threatening situation. The vehicle had to be towed back to the shop. The manager, who is not a certified mechanic, admitted he personally “fixed” the issue by tightening the fuel pump himself. A Mercedes-Benz diagnostic inspection later confirmed multiple severe assembly errors, including missing fasteners, unsecured oil cooler, disconnected vent lines, and other safety-related defects in the fuel and cooling systems. These unsafe and negligent repairs created an extreme fire hazard, engine instability, and risk of sudden failure while driving. I am requesting a formal NHTSA investigation into this matter to ensure vehicle safety compliance and to prevent similar incidents affecting other consumers.
NHTSA complaint #11696497 — an unverified report by a vehicle owner.
On Friday [XXX] at approximately [XXX]. My wife and I were driving our 2024 C-Class 300 (~8,000 miles on this vehicle) on [XXX] and entering the intersection of [XXX]. Riverside, CA 92506 when all of sudden the car just died (the engine stopped running, pushing the gas pedal with no power) and all the dashboard lights came on flashing like crazy. This incident paced my wife and I in a very venerable bad not safe situation. If there was any traffic at in this intersection at that moment it would have been a bad situation. I called MB Walter's they could hear the sounds which were loud and they ask me to open and close the doors to see if sound would stop and wait 5 minutes and try to restart. Waited 5 minutes car started and we drove it to Walter's. The week before I had it back in the service department because the finger print function was not working any longer. They supposedly replaced the software package and then this major issue happen. The service department at Walter's has tried at least two times to download a new software package however this vehicle is not allowing it to accept it. They said engineers from the East coast were trying to help but nothing has been accomplished. It is becoming frustrating and allowing the overall safety concern has been increasing for my wife and I. What if this happens again and we are on the freeway or a street with traffic which both situations could cause a severe accident and harm. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11692765 — an unverified report by a vehicle owner.
I am writing to formally report an ongoing issue and safety concern with my vehicle. Since the day I purchased the car, I have experienced numerous mechanical problems and have spent a significant amount of money on repairs. In August, I had to take my vehicle to a local repair shop three times due to persistent issues. The car was also towed by AAA three separate times for safety reasons. My main concern is that the vehicle hesitates during acceleration and feels sluggish while driving, which creates a serious safety risk on the road. I contacted Mercedes-Benz and filed a claim regarding this issue; however, I have not received any meaningful assistance or resolution. I am requesting that this matter be re-evaluated and properly addressed as soon as possible, as my safety and the reliability of the vehicle are at risk. Please confirm receipt of this message and advise me on the next steps or any documentation needed to proceed with my claim. Thank you for your prompt attention to this matter. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11691362 — an unverified report by a vehicle owner.
The sunroof is very glitchy and this is common in all Benz I have had a few different Benz and they all eventually have this same issue with their panoramic sunroof. Sometimes it opens half way life one side is up and the other side is closed and other times it will open fully but not close and other times it won’t open at all. This is a common problem that many Benz owners have stated this in the Benz forums all over. This is a safety issue due to unexpected weather conditions if it rains and it’s stuck inside gets damage and owners get wet which is also a distraction and may cause accidents. Please investigate this issue thoroughly. Their sunroofs should be recalled and extended warranties placed on them automatically by Mercedes Benz due to this being a very common issue in all model’s panorama sunroofs particularly C300s year 2017 thank you for looking into this matter.
NHTSA complaint #11665836 — an unverified report by a vehicle owner.
I had a A1 service completed on 5.23.25 with Mercedes Benz dealership in Sourh San Francisco. 2233 Gellert Blvd. On [XXX] 48 hrs later as I was leaving working- 4-5 blocks before entering the freeway, my car suddenly struggled to drive over 20MPH and the check engine light came on. I pulled over a block before entering freeway. I had it towed and got a Lyft’ ride home. It was a holiday weekend and I had to rent a car . Vehicle accessed 2 days later . I was told it needed a software update and there was a bulletin that came out in 2024 recommending to have the update and I needed to pay to have it repaired by performing a hard/soft upgrade . No empathy was evident . I said I knew nothing about it - dealership said they weren’t obligated to advise. I could have been in a collision or caused and accident and seriously injured had it occured while on freeway . This should be a recall as my life was at risk and so are others driving this year, make and model. The Mercedes Rep. told me she tested the car and was surprised by how it struggled to get past 20 mph, she thought maybe the mechanic had made an error a few days before. I feel very lucky I wasn’t in an accident- or a worst seriously injured! This bulletin warning should be a recall and looked into for a future recall that could save life’s. Knowing, this is a risk for a possible accident , it’s unacceptable that it is only a bulletin and not mandatory to share with owners of the this car. This was very scary and stressful situation. I was stuck in an area in Oakland, Ca known for high crime. In the end Mercedes waived the repair fee, they said under the circumstances and how my life was put as risk . I still think perhaps a wire or something may been disconnected- but no one will admit. Hence they waived fee. Please investigate , I look forward to your findings. Respectfully, [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11664002 — an unverified report by a vehicle owner.
ESP control unit software Recall 2016090002 Recall 2017110002 Recall 2020080016 And my car shows there’s cero recall active but is giving me problem showing code: U0121 u1110 U0122 B227d U0423 B227d
NHTSA complaint #11654348 — an unverified report by a vehicle owner.
When i scan my vehicle there are Mercedes Benz fault codes pertaining to the electrical system but also recalls that haven’t been done but when looking Mercedes Benz web site and NHTSA WEBSITE these are aren’t showing up as my particular chassis being included as part of the campaign
NHTSA complaint #11621666 — an unverified report by a vehicle owner.
The electrical wiring harness of my vehicle completely caught fire making my vehicle stopped working. Manufacture warranty refuses to acknowledge this as an ongoning issue with this models and forcing me to pay for my own repairs this is a danger to anyone driving this vehicle as the car entirely can be caught on fire at any given time.
NHTSA complaint #11596594 — an unverified report by a vehicle owner.
I was driving and all of a sudden a loud sound started occurring and the sound appeared to come from my breaks as if they were about to give out. The car is currently at Mercedes getting looked at. I’m concerned for my safety as I have taken this car in for two other issues in the last couple of months.
NHTSA complaint #11594999 — an unverified report by a vehicle owner.
The electronic system, specifically the battery, failed and it is available for inspection upon request. The persistent battery drain caused the vehicle to become inoperable multiple times, including an incident where I was stranded 200 miles from home with my wife and dog, posing significant safety risks. Yes, the defect has been confirmed by the dealership’s service center multiple times. The vehicle has been inspected by the dealership’s service technicians. Yes, the first malfunction message appeared on [XXX] at 2:22 PM, a week after purchase. Multiple warning messages have appeared since then, including transmission malfunction, running lights malfunction, high beams malfunction, and additional battery malfunction. Defect Description: - Description of the Defect: Persistent battery drain and related electronic system issues. - Date First Appeared: [XXX], a week after purchase. - Subsequent Occurrences: Multiple instances including being stranded 200 miles from home due to a dead battery and transmission error. Repair Attempts: I have taken my vehicle to [Dealership Name] for repairs on multiple occasions. Despite these efforts, the defect persists. Below are the details of each repair attempt: - Repair Attempt 1: [XXX], 2023, Battery replaced. - Repair Attempt 2: [XXX], 2024, Dealer refused to replace battery and simply charged it. Issue persisted the next day. - Repair Attempt 3: [XXX] 2024, Dealer didn't get back to me yet. Roadside Assistance Calls: - [XXX] 2022: First roadside assistance call for a dead battery. - [XXX], 2024: Roadside assistance called again. - [XXX], 2024: Roadside assistance called again. - [XXX], 2024: Roadside assistance called again. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11592228 — an unverified report by a vehicle owner.