Which parts fail
Components named in complaints (battery, alternator, wiring, ignition, instrument cluster, infotainment).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2017 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
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. …
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.
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. …
The contact owns a 2017 Mercedes-Benz C300. The contact received notification of NHTSA campaign number: 21V058000 (Communication, Electrical System) however, the part to do the recall repair was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The local dealer claimed that the manufacturer was responsible for the recall repair. The manufacturer was not made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.
I was reversing my vehicle when I heard a snap, and the inside dash panel warning sign came on...later I google it and found out it has happened to many other people. the clock spring behind the steering wheel snapped and airbags warning signs came on with possibility of deploying at any moment.
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
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
When I started my car, the dash did not reveal park, drive, or reverse. It illuminated with a warning light indicating an Electronic Stability Problem (ESP). Research revealed this to be an important safety feature and that the Mercedes-warning-lights-electric-stability-control may have problems with traction control requiring attention. The ESP light was NOT flashing for the system to intervene - as the car was parked in my garage. It did not light up with the word 'OFF' to assess whether it may have been inadvertently deactivated. The light stayed on indicating a suddenly improperly working ESP system. The light remained on after stopping and restarting the engine several times as the dealer maintenance technician suggested concluding with my vehicle being towed to Mercedes Benz of Augusta for service. …
Tl* the contact owned a 2017 Mercedes-Benz c300c. The contact stated that while the vehicle was parked, they were informed that their vehicle was on fire. The vehicle's console had caught on fire. The contact stated the fire department had put out the fire. The vehicle was deemed totaled due to the entire inside being completely burned. There were no injuries. A report was filed by the fire department stating that the fire was caused by electrical failures. The dealer (Mercedes-Benz of stevens creek 4500 stevens creek blvd, san jose, ca 95129; [phone]) was made aware of the failure and informed the contact that their vehicle was not included in NHTSA campaign number: 17V114000 (electrical system, engine and engine cooling). The contact stated that approximately, two months ago a fuse line underneath the front passenger seat had failed and needed to be replaced. …
The 2017 Mercedes-Benz C300 vehicle suffered a complete loss of power/electrics while in motion at speed and in traffic, causing the vehicle to unexpectedly stop on two separate occasions. The loss of all electrical supply leaves the vehicle immobile, without warning indicators and cannot be moved. The first incident was around 5 pm in a busy road junction in the dark, with limited lighting. As the vehicle is black colored it it is difficult to see in these circumstances. The second incident was at another busy road junction in heavy traffic, at midday on a Saturday. On both occasions the police had to attend as the immobilized vehicle posed a serious hazard with a risk of causing a collision to other road users. The approximate times to get the vehicle removed from the road in these two incidents were between 45 - 60 minutes. The period between the two incidents was 11 days. …
Related recalls
Electrical system › Starter assembly
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2015-2017 C300 4Matic, C300, CLA250, CLA250 4Matic and CLA45 AMG vehicles, 2017 C300 4Matic Cabrio, C300 4Matic Coupe, C300 Cabrio, C300 Coupe, E300, E300 4Matic, E400 4Matic Wagon, E43 AMG 4Matic, GLA250, GLA250 4Matic and GLC300 4Matic Coupe vehicles and 2016 C350e and…
Remedy: MBUSA will notify owners, and dealers will install an additional fuse in the electrical line to the starter, free of charge. The recall began August 31, 2017. Owners may contact MBUSA customer service at 1-800-367-6372.
Electrical complaints in other C300 years
Frequently asked questions
How common are electrical problems on the 2017 Mercedes-Benz C300?
NHTSA has 31 complaints about the electrical system of the 2017 Mercedes-Benz C300, 14% of the model year's 216 complaints. The component named most often is software (1 mentions).
Is there a recall for 2017 Mercedes-Benz C300 electrical problems?
Yes — NHTSA recall 17V-114 (starter assembly, Feb 23, 2017). Recall repairs are free at authorized dealers.
At what mileage do 2017 Mercedes-Benz C300 electrical problems start?
Half of the complaints with a recorded mileage happened before about 45,000 miles, and 33% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 2 fires and 0 injuries to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.