2017 Mercedes-Benz C 300 problems & reliability
215 owner complaints filed with NHTSA for the 2017 Mercedes-Benz C 300, alongside 15 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
12 complaints report injuries (16 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Engine | 77 | 36% |
| Unknown OR Other | 33 | 15% |
| Electrical System | 31 | 14% |
| Fuel/propulsion System | 30 | 14% |
| Structure | 24 | 11% |
| Seat Belts | 21 | 10% |
| Air Bags | 15 | 7% |
| Steering | 13 | 6% |
| Power Train | 12 | 6% |
| Visibility | 7 | 3% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Mileage when problems occurred
Half of the failures with a reported odometer reading occurred by 34,000 miles (middle 50% between 15,000 and 53,000 miles), based on 53 complaints that included mileage.
Complaints by incident year
What owners report
“2017 Mercedes c300 the switchover valve in the diagnostic module of the evaporative emission control system is jammed open. This issue was called for recall for models 2018 or later, but 2017 was not part of it.”
Engine · filed Jul 27, 2026
“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…”
Engine · filed May 15, 2026
“Check engine light for P052E which has been coming and going off for years now. Now the check engine light is there permanently. I spoke to Mercedes Benz customer service and requested for them to fix the problem now that the light is on permanently but they refuse to fix it because the car has 222,000 miles on it…”
Engine · filed Mar 20, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Desiccated Air Bag Inflator Rupture
Engineering Analysis EA21002 · opened Sep 17, 2021 · open
Technical service bulletins
160 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2017 Mercedes-Benz C 300. The 10 most recent:
Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause…
LI35.30-P-058566 · Service Bulletin/Repair Instructions · issued Jul 14, 2026
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than…
PSL-NCU Return Parts 6/19 · Other · issued Jun 19, 2026
Complaint Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop menu, e.g., 505 or 550A, which includes a service A. Cause The root cause is currently being…
LI00.20-P-080703 · Service Bulletin/Repair Instructions · issued Jun 12, 2026
Complaint After successful commissioning of the HERMES control unit (N112/9) with XENTRY Diagnosis DVD 03/2026, the message "SOS - service not activated" appears on the instrument cluster. In addition, the following two…
LI82.85-P-080507 · Service Bulletin/Repair Instructions · issued May 26, 2026
Complaint The customer requests deactivation of the N112/9 HERMES communication module Note: Deactivation of the HERMES control unit (N112/9) is not supported for gray-market vehicles. Cause Before deactivating the…
LI82.85-P-080559 · Service Bulletin/Repair Instructions · issued May 26, 2026
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than…
PSL-NCU Return Parts 5/22 · Other · issued May 22, 2026
Complaint There are several types of complaint about noises or poor windshield wiper wiping performance: A: Wiper blades squeaking, chattering, shuddering B: The windshield is not wiped completely (streaking) C: During…
LI82.30-P-059239 · Service Bulletin/Repair Instructions · issued May 19, 2026
The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, June 4, 2026. After…
PSL-NCU Return Parts 5/15 · Other · issued May 15, 2026
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…
LI54.65-P-080132 · Service Bulletin/Repair Instructions · issued May 12, 2026
Complaint Damaged cords/tensioning cables at the soft top interior trim with the following characteristics: - Cord/tensioning cable torn - Cord/tensioning cable worn - Cord/tensioning cable torn out - Cord/tensioning…
LI77.30-P-070145 · Service Bulletin/Repair Instructions · issued Apr 28, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2017 Mercedes-Benz C 300 has 15 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2017 Mercedes-Benz C 300?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.
- · Owners most often reported problems around 34,000 miles — budget accordingly if the car is approaching that mileage.