AI Damage2018 Mercedes-Benz C 300: common problems
The maker issued 160 service bulletins for this year. Details by component below, with sources.
Key figures
- Technical service bulletins (TSB)
- 160
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Electrical system | 0 | 0 | 50 |
| Powertrain | 0 | 0 | 31 |
| Equipment | 0 | 0 | 19 |
| Exterior lighting | 0 | 0 | 16 |
| Engine | 0 | 0 | 15 |
| Structure | 0 | 0 | 11 |
| Visibility | 0 | 0 | 11 |
| Engine and cooling | 0 | 0 | 10 |
| Fuel/propulsion system | 0 | 0 | 7 |
| Steering | 0 | 0 | 6 |
| Backover prevention | 0 | 0 | 3 |
| Seats | 0 | 0 | 2 |
| Suspension | 0 | 0 | 2 |
| Communication | 0 | 0 | 1 |
Comparison
What to check before buying
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Powertrain. Shift quality under load, harsh shifts, transmission codes, CV joints.
- Exterior lighting. Headlamps, leveling, sensors and mounts after a frontal hit.
- Engine. Cold start, unusual noises, oil leaks and engine codes.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- 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…
- Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic…
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…
- 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…
- 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…
- Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic…
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…
- Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same…
Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering…
- Dear Mercedes-Benz Owner
In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA is extending the warranty coverage for the Diagnostic Module for…
- Complaint • Harsh 1‑2, 2‑3, and/or 3‑4 shift • Jerky shifting • Jolting when accelerating from stop Cause…
Complaint • Harsh 1‑2, 2‑3, and/or 3‑4 shift • Jerky shifting • Jolting when accelerating from stop Cause Insufficient software application causing elevated K81/K27/B05 fill time adaptations and elevated torque…
- Complaint Tailgate opens unintentionally
Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th generation, the vehicle key can be recoded so…
- Complaint A popup is seen on the HU with the message "data connection temporarily not available"
Potentially affected functionalities in NTG4.5, NTG5 1.Weather 2.Local Search 3.IP Radio 4.Send2Car 5.Speech Detection Service 6.Navigation 7.iHeartRadio 8.Traffic Cams Cause MB Apps is sundowned for all vehicles with…
- 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 Various root…
- Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns
It will also ensure that if a case is necessary, all supporting documentation is available. This should not be used on its own as justification for creating a TIPS case. Cause The root cause will vary depending on the…
NHTSA lists 160 bulletins for this year; the 12 newest are shown here.
Other years of this model
Questions and answers
What are the most common problems with the 2018 Mercedes-Benz C 300?
There are no owner complaints in the NHTSA data for this year; the data comes from 160 manufacturer service bulletins.
How many service bulletins (TSB) were issued for the 2018 Mercedes-Benz C 300?
NHTSA lists 160 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2018 Mercedes-Benz C 300 from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2018 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-04.