NHTSA (USA)High Risk
At a glance
What can fail
The front roof panel between the windshield and panoramic sunroof may have been improperly bonded during a prior repair, causing the panel to detach from the vehicle.
This page covers 15 recalls, 215 owner complaints and EPA fuel economy for the 2017 Mercedes-Benz C300.
26–28 mpg combined
8.4–9 L/100km
Subcompact Cars
Fuel economy data from fueleconomy.gov (EPA / U.S. Dept. of Energy). Annual cost based on 15,000 mi/yr at 55% city driving and current fuel prices. MPG is U.S. gallons; L/100km converted. Ranges reflect the 2 tested variants for this model year.
Engine and fuel system complaints dominate what owners report for the 2017 Mercedes-Benz C300. On the engine side, owners frequently describe check engine lights that cycle on and off before becoming permanent, often tied to codes related to engine warm-up or cold-start performance. Some describe the light persisting well into higher mileage with no resolution from the dealer. Fuel system complaints center heavily on a strong gasoline smell inside and outside the cabin, reported both while driving and after the vehicle is parked. Owners describe noticing the odor when the air conditioning is running or shortly after shutting the engine off. Seat belt complaints are the third most-reported system, though the specific symptoms described there are less consistent across the complaint set. The fuel smell pattern is the most recurring sensory symptom owners flag across multiple independent reports.
215
Total Complaints
10
Crash-Related
3
Fire-Related
12
With Injuries
By System
The 2017 Mercedes-Benz C300 has 15 recalls, the most serious involving a driver airbag that can deploy without warning, a starter component that can overheat and melt surrounding parts causing a fire, and a front roof panel that can detach from the vehicle and become a road hazard.
On the steering side, the rear-wheel drive variants can lose proper steering control due to a rack issue, and the electric power steering assist can cut out entirely if the motor's electrical contacts fail. Several recalls affect the front seats: seatbacks on coupe and cabriolet trims may not lock properly on one side and can fold forward in a crash, and the front seatbelt pretensioners may not function correctly, leaving occupants less protected. There is also a recall for front seatbelts that may not fully retract, which can discourage proper use.
Four recalls cover the emergency call system from different angles: the system can be disabled, can send responders to the wrong location, or can report an incorrect date and time, all of which delay emergency response after a crash. On the body side, cabriolet trims have a separate concern where rear beltline trim can separate from the vehicle while driving and become a road hazard.
At a glance
What can fail
The front roof panel between the windshield and panoramic sunroof may have been improperly bonded during a prior repair, causing the panel to detach from the vehicle.
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Complaints are owner-reported and reflect individual experiences, not confirmed defects. They are distinct from recalls. Data sourced from the national vehicle safety complaint database. See trending complaints →
What the fix does
Dealers will replace the front roof panel at no charge to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A software error in the communication module's SIM card can prevent mobile network connection, which disables the emergency call (eCall) system.
What the fix does
The communication module software will be updated at no cost through an over-the-air update or by a dealer.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The front roof panel between the windshield and panoramic sunroof may not be properly bonded to the vehicle from a previous repair, risking separation.
What the fix does
The dealer will remove and replace the front roof panel using proper bonding materials and procedures at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The communication module may have been turned off during service, disabling the Emergency Call function that connects your vehicle to emergency services.
What the fix does
Dealers will inspect the communication module and reactivate it if needed, at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The communication module software may fail to send your vehicle's correct location to emergency services when the eCall system activates during a crash.
What the fix does
A dealer will update the communication module software, or the update will be sent over-the-air, at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The front seat belts may not fully retract back into their stowed position after use.
What the fix does
Dealers will check the front seat belt retraction and adjust the damping foam in the B-pillars as needed at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A software error causes the eCall emergency system's date and time to be incorrect, which may result in an inaccurate vehicle location being sent during an emergency call.
What the fix does
Mercedes-Benz will send a remote software update to your vehicle. Dealers will verify the update worked or install a new communication module software at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The right side of the front seat seatback may not lock securely in place.
What the fix does
Dealers will inspect the seatback lock and replace it if needed at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A locknut in the steering rack may break under heavy load, potentially causing the steering to lock in one position.
What the fix does
Dealers will replace the steering rack at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A bonding problem during manufacturing can cause the rear beltline trim to separate from the vehicle.
What the fix does
Dealers will inspect the rear beltline trim and replace it if needed at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The right seatback on front seats may fail to lock properly, potentially allowing the seat to move unexpectedly.
What the fix does
Dealers will inspect the front seatback locks and replace them if needed at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The driver's airbag may deploy unexpectedly if the steering components lack proper grounding and the airbag clockspring is broken, allowing electrostatic discharge to trigger deployment.
What the fix does
Dealers will add grounding to the steering components to prevent electrostatic discharge from triggering the airbag.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The front seat seatbelt pretensioners may not work properly during a crash, reducing protection for front occupants.
What the fix does
Dealers will replace the front seat belts at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The electrical contacts connecting to the power steering motor may not be properly welded, potentially causing loss of electrical contact and power steering function.
What the fix does
Dealers will replace the electric power steering rack at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
When the engine or transmission won't start, the starter motor keeps trying to turn over. This repeated effort can cause the starting current limiter to overheat.
What the fix does
A dealer will install an additional fuse in the electrical line to the starter motor to protect against overheating.
Summarized — see the official notice for exact wording, dates, and contacts.