AI DamageMercedes-Benz S 450: problems, complaints, bulletins
Summary for the Mercedes-Benz S 450 across 3 model years: 14 owner complaints and 155 NHTSA service bulletins, plus repair videos. Pick a year for details.
Model years
What fails most often
- 1 Service brakes 21% of all complaints
- 2 Powertrain 14% of all complaints
- 3 Forward collision avoidance 14% of all complaints
- 4 Visibility 7% of all complaints
- 5 Fuel/propulsion system 7% of all complaints
- 6 Steering 7% of all complaints
- 7 Seat belts 7% of all complaints
- 8 Vehicle speed control 7% of all complaints
- Service brakes: 3 complaints (21% of all), 1 of them with a crash reported by the owner; manufacturer bulletins for this component: 3.
- Powertrain: 2 complaints (14% of all); manufacturer bulletins for this component: 92.
- Forward collision avoidance: 2 complaints (14% of all).
- Visibility: 1 complaints (7% of all); manufacturer bulletins for this component: 24.
- Fuel/propulsion system: 1 complaints (7% of all); manufacturer bulletins for this component: 15.
Symptoms owners describe
How many of the 14 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Service brakes | 3 | 1 | 3 |
| Powertrain | 2 | 0 | 92 |
| Forward collision avoidance | 2 | 0 | 0 |
| Visibility | 1 | 0 | 24 |
| Fuel/propulsion system | 1 | 0 | 15 |
| Steering | 1 | 0 | 15 |
| Seat belts | 1 | 0 | 0 |
| Vehicle speed control | 1 | 0 | 0 |
| Electrical system | 0 | 0 | 125 |
| Exterior lighting | 0 | 0 | 43 |
| Equipment | 0 | 0 | 31 |
| Structure | 0 | 0 | 22 |
| Suspension | 0 | 0 | 21 |
| Engine | 0 | 0 | 15 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
It first began a couple of weeks ago when (1) the side view mirrors no longer closed automatically 2) Next, while I was driving, the car yesterday, the seat belt suddenly tightened as the car prepared for a sudden impact (which there was none).3) Today, the car refused to stop when I backed it out of the garage.
The contact received notification of NTHSA Campaign Number: 26V216000 (Power Train); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair.
The fuel pump My car stopped on the highway [XXX] on [XXX] with my children in the car with no warning at all. I was so lucky nobody hit us and it took 20 minutes of trying to start it to get off of the highway to a gas station where it cut off again The dealer said it is a known problem however my vin number was…
Additionally, the check engine warning light was later illuminated. The vehicle was taken to the dealer where it was diagnosed with transmission valve body failure. The contact was informed that the transmission valve body needed to be replaced. The vehicle was not repaired.
Had windshield breakage and replacement on 14 December 2023. On 29 January 2024, had an apparent windshield strike (pinhead size) and windshield cracked from middle to top. Within 20 minutes crack had spread all across the top of windshield.
Steering wheel became extremely stiff to turn and a message that read âsteering malfunction increase physical effortâ appeared while driving at around 30 mph while in a vacation trip, not only was this extremely unsettling since it happened suddenly but I had to act fast to avoid a collision with other vehicles,…
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
What to check before buying
- Service brakes. Pedal feel, ABS operation, leaks, discs and hoses.
- Powertrain. Shift quality under load, harsh shifts, transmission codes, CV joints.
- Forward collision avoidance. Radar and camera: calibration after bumper or windshield replacement.
- Visibility. Wipers, mirrors, defrosters, cracked glass.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- Complaint Clanking noise from the area of the speakers in the doors
- Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic…
- Complaint Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE
- Complaint Noises in the steering column area when steering. See example file in the attachments area
- Complaint Only vehicles with a variable transfer case are affected
- Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic…
- Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same…
- Dear Mercedes-Benz Owner
- Complaint Tailgate opens unintentionally
- Complaint A popup is seen on the HU with the message "data connection temporarily not available"
- Complaint Clanking noise from the area of the speakers in the doors
- Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns
Repair videos
We do not copy videos: these are YouTube links credited to their authors. Amounts are as stated by the author and not verified by us.
Other models of this make
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 2026-11-05.