2009 Mercedes Benz C300: what breaks, and at what mileage
What breaks on the 2009 Mercedes Benz C300
On the 2009 Mercedes Benz C300, the failure owners report most often is airbag inflator rupture, and the reports cluster around 90,000 miles. The earliest to appear is tail light, brake light or signal failure, reported by a median of 57,500 miles. Overall it scores 73 out of 100, high risk for a 2009.
High risk for a 2009 — 78th riskiest of the 295 2009 vehicles we can rate. 846 owner reports; fleet size estimated from this year's own recall paperwork.
What breaks on the 2009 Mercedes Benz C300
Owners have reported 48 named failure modes on the 2009 Mercedes Benz C300, and the three most-reported carry 37% of everything filed.
Airbag inflator rupture leads with 130 reports, about 12 per 1,000 vehicles and with the middle half of reports between 59k to 112,500 miles.
No-start or intermittent start failure follows with 117 reports, usually reported between 70k to 101,000 miles.
Other electrical problem follows with 67 reports, usually reported between 54k to 82,500 miles. 4 of those reports mention a fire.
By system, the reports fall mostly into airbag (151), electrical (135) and engine (130).
When these failures get reported
560 of the reports on the 2009 Mercedes Benz C300 came with an odometer reading, and half of those were filed before 70,000 miles.
Cumulatively, 18% by 50,000 miles, 82% by 100,000 miles and 98% by 150,000 miles of the dated reports had been filed, with 1 filed above the top of the chart.
The busiest stretch is between 70,000 and 80,000 miles, which alone holds 17% of the dated reports.
7% of the dated reports were filed below 36,000 miles, so this is mostly a story about older, higher-mileage cars.
In the order they tend to show up: tail light, brake light or signal failure around 57k, steering column or shaft failure around 58k, other lighting problem around 58k and ignition switch, key fob or immobilizer failure around 60k.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
Showing the 12 most-reported failure modes of 48. The full list is in the table below.
How reports accumulate
Every report with an odometer reading, cumulative, from 0 to 200,000 miles. A further 1 report came in above that, which is why the line stops short of the top. A curve that climbs early is a car with early problems, whatever its total.
- Line share of reports filed by that mileage
- Dashed the median reported mileage
Severity, and what it costs
Across the named modes, 17 mention a crash, 30 a fire and 14 an injury. Those are the words owners used in their own complaints, and NHTSA does not verify them, but they are the closest thing in this data to a measure of what a failure actually did.
The average severity weight across every report on this year is 4.08, where a stalled engine or a failed airbag weighs many times more than a rattling trim panel, and a figure this high means the reports are dominated by failures with safety consequences rather than annoyances. The weighting is set out in full on the methodology page.
What the top failures cost to put right, as editorial estimates for an independent US shop rather than figures from NHTSA: airbag inflator rupture at $0–$0, no-start or intermittent start failure at $200–$1,800, other electrical problem at $250–$2,000 and tail light, brake light or signal failure at $100–$900. Dealer labour, a seized bolt or a part that is no longer made can push any of these past the top of its range.
18% of the reports on this year sit in the engine, transmission, drivetrain or cooling systems — the four where a repair bill is usually four figures.
Every reported failure mode
| Failure mode | System | Reports | With reading | 25th | Median | 75th | Per 1,000 | Typical repair | Severity |
|---|---|---|---|---|---|---|---|---|---|
| Airbag inflator rupture | airbag | 130 | 29 | 59k | 90k | 112k | 12.3 | $0–$0 | Critical |
| No-start or intermittent start failure | engine | 117 | 100 | 70k | 81k | 101k | 11.1 | $200–$1,800 | Moderate |
| Other electrical problem | electrical | 67 | 54 | 54k | 73k | 84k | 6.4 | $250–$2,000 | Moderate |
| Tail light, brake light or signal failure | lighting | 62 | 48 | 52k | 57k | 63k | 5.9 | $100–$900 | Moderate |
| Control arm, ball joint or bushing failure | suspension | 56 | 30 | 72k | 87k | 125k | 5.3 | $400–$2,200 | High |
| Other steering problem | steering | 55 | 42 | 57k | 76k | 90k | 5.2 | $350–$2,400 | High |
| Ignition switch, key fob or immobilizer failure | electrical | 41 | 35 | 53k | 60k | 79k | 3.9 | $250–$1,500 | High |
| Other lighting problem | lighting | 39 | 32 | 49k | 58k | 76k | 3.7 | $120–$1,200 | Moderate |
| Wiring harness or short circuit | electrical | 23 | 17 | 46k | 63k | 70k | 2.2 | $400–$3,500 | High |
| Headlight failure or clouding | lighting | 20 | 15 | 24k | 62k | 95k | 1.9 | $150–$1,800 | Moderate |
| Steering column or shaft failure | steering | 15 | 15 | 49k | 58k | 65k | 1.4 | $600–$2,500 | Critical |
| Airbag warning light or occupant sensor fault | airbag | 12 | 11 | 62k | 75k | 78k | 1.1 | $300–$1,600 | High |
| Overheating | cooling | 11 | 9 | 36k | 62k | 70k | 1.0 | $400–$3,500 | High |
| Other engine problem | engine | 11 | 10 | 58k | 67k | 94k | 1.0 | $300–$4,000 | High |
| Fuel tank, filler or EVAP failure | fuel | 9 | 5 | — | 120k | — | 0.9 | $250–$1,800 | Moderate |
| Other suspension problem | suspension | 9 | 2 | — | 99k | — | 0.9 | $350–$2,000 | Moderate |
| Instrument cluster or gauge failure | infotainment | 8 | 7 | — | 70k | — | 0.8 | $350–$1,400 | Moderate |
| Other brake problem | brakes | 8 | 6 | — | 56k | — | 0.8 | $300–$1,800 | High |
| Other wheel or tire problem | wheels | 8 | 6 | — | 36k | — | 0.8 | $200–$1,500 | High |
| Other body or interior problem | body | 8 | 6 | — | 104k | — | 0.8 | $200–$2,000 | Moderate |
| Parking brake failure | brakes | 6 | 6 | — | 88k | — | 0.6 | $250–$1,300 | Moderate |
| Seat belt or retractor failure | airbag | 6 | 5 | — | 65k | — | 0.6 | $200–$900 | High |
| Rust or structural corrosion | body | 6 | 6 | — | 72k | — | 0.6 | $500–$6,000 | High |
| Other driver assistance problem | adas | 6 | 3 | — | 80k | — | 0.6 | $250–$1,800 | High |
| Tire pressure monitor failure | wheels | 5 | 5 | — | 65k | — | 0.5 | $80–$600 | Low |
| Other speed control problem | adas | 5 | 5 | — | 36k | — | 0.5 | $250–$2,000 | Critical |
| Loss of power steering | steering | 4 | 4 | — | 63k | — | 0.4 | $600–$2,800 | Critical |
| Fuel leak or fuel odor | fuel | 3 | 3 | — | 120k | — | 0.3 | $300–$2,500 | Critical |
| Electrical fire or melted wiring | electrical | 2 | 0 | — | — | — | 0.2 | $1,500–$9,000 | Critical |
| Radiator or coolant leak | cooling | 2 | 0 | — | — | — | 0.2 | $350–$1,900 | High |
| Complete transmission failure | transmission | 2 | 2 | — | 41k | — | 0.2 | $2,800–$8,000 | Critical |
| Control module (ECM/PCM/BCM) failure | electrical | 2 | 1 | — | 140k | — | 0.2 | $700–$3,000 | High |
| Airbag failed to deploy in a crash | airbag | 2 | 2 | — | 45k | — | 0.2 | $1,000–$5,000 | Critical |
| Tire blowout or tread separation | wheels | 2 | 2 | — | 55k | — | 0.2 | $200–$1,500 | Critical |
| Sunroof failure or glass breakage | body | 2 | 2 | — | 49k | — | 0.2 | $700–$4,500 | High |
| Other powertrain problem | transmission | 2 | 0 | — | — | — | 0.2 | $400–$4,500 | High |
| Other fuel system problem | fuel | 2 | 2 | — | 60k | — | 0.2 | $300–$2,200 | High |
| Oil leak | engine | 1 | 1 | — | 90k | — | 0.1 | $250–$2,200 | Moderate |
| Misfire or rough idle | engine | 1 | 1 | — | 13 | — | 0.1 | $250–$1,600 | Moderate |
| Thermostat failure | cooling | 1 | 1 | — | 56k | — | 0.1 | $250–$900 | Moderate |
| Differential or transfer case failure | drivetrain | 1 | 1 | — | 38k | — | 0.1 | $900–$4,200 | High |
| Loss of braking | brakes | 1 | 0 | — | — | — | 0.1 | $400–$3,000 | Critical |
| Master cylinder or brake booster failure | brakes | 1 | 0 | — | — | — | 0.1 | $450–$2,200 | Critical |
| Premature brake pad or rotor wear | brakes | 1 | 1 | — | 35k | — | 0.1 | $300–$1,400 | Moderate |
| Brake line, hose or caliper failure | brakes | 1 | 0 | — | — | — | 0.1 | $250–$1,600 | Critical |
| Cruise control failure | adas | 1 | 1 | — | 10 | — | 0.1 | $200–$1,400 | High |
| Door latch or handle failure | body | 1 | 1 | — | 56k | — | 0.1 | $250–$1,200 | High |
| Other seat belt problem | airbag | 1 | 0 | — | — | — | 0.1 | $200–$900 | High |
| Unclassified problem | other | 67 | 26 | 64k | 77k | 85k | 6.4 | — | Moderate |
Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound. Repair costs are typical independent-shop ranges for the failure, not figures from these reports.
How often, against how many were built
Scaled by an estimate of how many of these cars exist, the 2009 Mercedes Benz C300 draws about 80 per 1,000 vehicles, which puts it in the 97th percentile of complaint rates among 2009 vehicles we can rate.
That denominator is the weakest number on the page and it is fair to say so plainly. Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound.
The working figure is 10,536 vehicles. If the true number is twice that, every rate on this page is half what it says; the ranking against other 2009 vehicles, which is what the risk score uses, is far more robust than the rate itself.
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The odometer reading is the one the owner gave.
Airbag inflator rupture
Takata recall from dec 2015 first notice from dealer it's been faulty for a long time now and have concerns about my safety while driving obviously it's well past 60 days can we put some pressure on them. Fix it now!!!!
Takata recall from dec 2015 first notice from dealer it's been faulty for a long time now and have concerns about my safety while driving obviously it's well past 60 days can we put some pressure on them. Fix it now!!!!
No-start or intermittent start failure
My car left me stranded at work. When I was leaving work my car would not start the steering was completely locked . The car would not even start the only thing that would turn on was the radio and a message of not to forget to remove your key. I could not even get the car out of gear. I would crank it and nothing, it was completely dead. I never received a message to warn me that something was faulty.. Before taking car into dealership I did my research online and spoke with a service tech at mercedes and said that it was possibly eis failure and steering lock. After so many complains like mine online I can't believe there is not a recall on this. I believe this is a safety hazard. What if this would of happened when I was driving and my steering locked? Who knows?...is mercedes waiting for serious accidents to happen? These failures are really a call for a recall..if there are anymore mercedes owners out there with the same problem file your complaints maybe if more of us complain they will do a recall. This is not cheap to fix it cost from $1200 to $1700. I bought a mercedes believing I was buying a dependable vehicle now I am…
My car left me stranded at work. When I was leaving work my car would not start the steering was completely locked . The car would not even start the only thing that would turn on was the radio and a message of not to forget to remove your key. I could not even get the car out of gear. I would crank it and nothing, it was completely dead. I never received a message to warn me that something was faulty.. Before taking car into dealership I did my research online and spoke with a service tech at mercedes and said that it was possibly eis failure and steering lock. After so many complains like mine online I can't believe there is not a recall on this. I believe this is a safety hazard. What if this would of happened when I was driving and my steering locked? Who knows?...is mercedes waiting for serious accidents to happen? These failures are really a call for a recall..if there are anymore mercedes owners out there with the same problem file your complaints maybe if more of us complain they will do a recall. This is not cheap to fix it cost from $1200 to $1700. I bought a mercedes believing I was buying a dependable vehicle now I am…
Other electrical problem
At 5:00pm, I was driving the mercedes benz c300, year 2009, 9010 miles in the parking lot of ymca in la canada, ca at 3 miles/hr. I prepared to stop the car and stepped on the brake, suddenly, the engine rev up and accelerated. The car jumped over the stop bumper but I pressed very hard on the brake and finally the car stopped and the engine was off. The front of the car was about 2 feet from the wall at the parking lot. I was so scared because it was the first time I experienced the unintended acceleration. I went to the gym and at 6:30pm I drove the car back home, it is about 6 miles from my house. I really feel unsafe with my almost brand new mb. I'll take off for work next monday and will take the car to the dealer for checking. I was lucky this time with no damage or injury because I was driving very slowly in the parking lot and ready to stop. However I don't want to take the chance next time, it's so dangerous, I can get kill or somebody can get hurt if my car jumps again. I do the research and see the complaint # 10330370 on 05/23/2010. The case was almost the same: when the driver stepped on the brake and the mb…
Warning indicators flashed for all the right side rear lights. When I went to change bulbs discovered the covering on wires had melted along with the plastic harness. Took it to dealer next day and the harness had to be replaced for a little over $150. It is happening on the other side also. Service rep has seen on other c300s. Mb denies this is a defect. *tr
Recalls on the 2009 model year
NHTSA has issued 8 recall campaigns covering the 2009 Mercedes Benz C300, affecting an estimated 39,935 vehicles. A recall is a different kind of evidence from a complaint: it is the regulator and the manufacturer agreeing that something has to be fixed, and the fix is free for as long as the car exists.
The campaigns cover exterior lighting:lighting control module:software, air bags:frontal:passenger side:inflator module and air bags:frontal:sensor/control module-inactive. Whether the work was actually done on the car in front of you is a question only the VIN can answer, and the manufacturer or NHTSA will answer it free.
Recalls also distort complaint counts. Publicity about a campaign reminds owners that complaining is possible, so reports for a recalled component often spike after the recall rather than before it.
EXTERIOR LIGHTING:LIGHTING CONTROL MODULE:SOFTWARE
22 vehicles 2022-03-18- Defect
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2010 E350, 2014 G550, 2008-2009 C300, 2008 C350, 2009 CLK550, 2007 SL550, SLK280, and 2008 SLK350 vehicles. Various control units may have been updated with incorrect software configuration during a service repair. This can result in various system failures, such as loss of drive power, reduced exterior lighting, or loss of dynamic control functions, including stability and traction control.
- Consequence
- Various system failures, such as loss of drive power, reduced exterior lighting, or loss of dynamic control functions including stability and traction control, can increase the risk of a crash.
- Remedy
- Dealers will update the software configuration on the affected control units, free of charge. Owner notification letters were mailed May 3, 2022. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2022040003.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE
132,167 vehicles 2018-01-10- Defect
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2013 C250, C250 Coupe, C350 Coupe 4Matic, C300 4Matic, C350, C350 Coupe, C63 AMG, C63 Coupe, E350 Cabrio, E350 Coupe, E550 Cabrio, E350 Coupe 4Matic, E550 Coupe, GLK350 4Matic, GLK250 Bluetec 4Matic, GLK350, SLS Coupe, SLS AMG GT Coupe, and SLS Roadster vehicles sold, or ever registered, in the states of Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S. Virgin Islands or "Zone A."…
- Consequence
- An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
- Remedy
- MBUSA will notify owners, and dealers will replace the passenger frontal air bag module, free of charge. Mercedes issued an interim notification to owners on February 23, 2018. A second notice will be mailed when remedy parts are available. Owners may contact MBUSA customer service at 1-877-496-3691.
AIR BAGS:FRONTAL:SENSOR/CONTROL MODULE-INACTIVE
51 vehicles 2017-03-14- Defect
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2016 AMG GT-S, GLC300, CLA250 and GLE300d 4Matic vehicles, 2013 C250, E350 BlueTec and G63 AMG vehicles, 2008-2014 C300 vehicles, 2013-2014 C300 4Matic and ML350 4Matic vehicles, 2009 C350 vehicles, 2014 CLS550, E350 4Matic, E350 Coupe 4Matic, E350 Wagon 4Matic, GLK350 and SL550 vehicles, 2012 CLS550 4Matic vehicles, 2012-2016 E350 vehicles, 2016-2017 GL450 4Matic vehicles, 2012-2014 ML350 4Matic BlueTec vehicles, 2015 S550, S550 4Matic and C300 4Matic Sedan vehicles, 2015-2016 C300 Sedan vehicles, and 2017 SL63 AMG…
- Consequence
- If the air bags do not deploy as intended in the event of a crash, there would be an increased risk of injury in the event of a crash.
- Remedy
- MBUSA will notify owners, and dealers will update software in the affected control units, free of charge. The recall began April 21, 2017. Owners may contact MBUSA customer service at 1-800-367-6372.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE
104,119 vehicles 2017-01-10- Defect
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2012 C300 4Matic, C250, C250 Coupe, C350, C350 Coupe 4Matic, C350 Coupe, C63 AMG, C63 AMG Coupe, E350 Coupe 4Matic, E350 Cabrio, E350 Coupe, E550 Cabrio, E550 Coupe, GLK350 4Matic, GLK350, SLS AMG Cabrio, and SLS AMG Coupe vehicles originally sold, or ever registered, in Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S. Virgin Islands, or "Zone A." Additionally, unless included in "Zone A"…
- Consequence
- An inflator rupture may result in metal fragments striking the vehicle occupants resulting in serious injury or death.
- Remedy
- MBUSA will notify owners, and dealers will replace the front passenger air bag modules, free of charge. Owners were sent an interim notification in March 2017. Second notices started going out in October 2018 and continue to be mailed as parts become available. Owners may contact MBUSA customer service at 1-877-496-3691
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE
258,163 vehicles 2016-05-26- Defect
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain model year 2008-2011 C300 Sedan, C300 4matic Sedan, C350 Sedan, C63 AMG Sedan vehicles, 2010-2011 GLK350, GLK350 4-Matic and E350 Coupe vehicles, 2011 SLS AMG, E350 Convertible, E550 Coupe and E550 Convertible vehicles originally sold, or ever registered, in Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S. Virgin Islands, or "Zone A." Additionally, unless included in "Zone A" above, MBUSA is…
- Consequence
- An inflator rupture may result in metal fragments striking the vehicle occupants resulting in serious injury or death.
- Remedy
- MBUSA will notify owners, and dealers will replace the passenger frontal air bag modules, free of charge. Owners were sent an interim notification October 2016. A second notice will be mailed when remedy parts are available. Owners may contact MBUSA customer service at 1-877-496-3691.
AIR BAGS:FRONTAL:DRIVER SIDE:INFLATOR MODULE
711,159 vehicles 2016-02-11- Defect
- Mercedes-Benz USA, LLC. (MBUSA) is recalling certain model year 2009-2010 ML320 BlueTec 4Matic, GL320 BlueTec 4Matic and R320 CDI 4Matic, 2011 E350 Cabriolet and E550 Cabriolet, 2009-2011 ML350, ML350 4Matic, ML550 4Matic, ML63 AMG, and C63 AMG, 2010-2011 ML450 4Matic Hybrid, E350 Coupe, E350 4Matic, E550 Coupe, E550 4Matic, and E63 AMG, 2011-2012 GL350 BlueTec 4Matic and R350 BlueTec 4Matic, 2009-2012 GL450 4Matic, GL550 4Matic and R350 4Matic, 2007-2008 SLK280, SLK350, and SLK55 AMG, 2011-2014 SLS AMG Coupe, 2012 SLS AMG Cabriolet, 2013-2014 SLS AMG GT and SLS AMG GT…
- Consequence
- In the event of a crash necessitating deployment of the driver's frontal air bag, the inflator could rupture with metal fragments striking the driver or other occupants resulting in serious injury or death.
- Remedy
- MBUSA will their notify owners, and Fiat Chrysler will notify the affected Chrysler owners. Dealers for the respective brands will replace the driver's frontal air bag module, free of charge. This recall began November 2016. Mercedes-Benz owners may contact MBUSA customer service at 1-800-367-6372 and Chrysler owners may contact Fiat Chrysler customer service at 1-800-853-1403.
AIR BAGS:FRONTAL:SENSOR/CONTROL MODULE-INACTIVE
127,504 vehicles 2015-10-27- Defect
- Mercedes-Benz USA, LLC. (MBUSA) is recalling certain model year 2008-2009 C300 Sedan, C300 4Matic, C63 AMG, and C350 vehicles, and 2010 GLK350 and GLK350 4Matic vehicles. Due to a manufacturing error, the air bag control unit may corrode and cause the control unit to malfunction.
- Consequence
- The malfunctioning air bag control unit may cause the air bags to unexpectedly deploy increasing the risk of injury and the possibility of a vehicle crash. Alternatively, the air bag control unit malfunction may cause the air bags to not deploy in the event of a crash necessitating air bag deployment, increasing the risk of occupant injury.
- Remedy
- MBUSA will notify owners, and dealers will inspect the air bag control unit and replace it, as necessary, free of charge. Mercedes-Benz issued an interim notification to owners on December 23, 2015. The recall began on March 14, 2016. Owners may contact MBUSA customer service at 1-800-367-6372.
EXTERIOR LIGHTING:TAIL LIGHTS
252,867 vehicles 2014-04-11- Defect
- Mercedes-Benz USA, LLC (Mercedes) is recalling certain model year 2008-2011 C300, C300 4Matic, C350, and C63 AMG vehicles manufactured January 26, 2007, through July 13, 2011. In the affected vehicles, a poor electrical ground connection may result in the dimming or failure of the tail lights.
- Consequence
- Dimming or failure of the tail lights reduces the ability to warn other motorists of the driver's intentions of stopping or turning, increasing the risk of a crash.
- Remedy
- Mercedes will notify owners, and dealers will replace the bulb holders if not previously updated and replace any corroded connectors, free of charge. The recall began on August, 18, 2014. Owners may contact Mercedes at 1-800-367-6372.
Recall work is free at a franchised dealer regardless of the car's age. Check the VIN at nhtsa.gov/recalls before assuming it was done.
How it ranks in the 2009 field
The score at the top of the page, placed among its peers. The zones are the same thresholds the scorer applies, read out of the scorer itself, so the picture and the band word cannot disagree.
Scores are ranked within the model year, never across years, because an older car has had longer to accumulate reports.
- Left fewer and less serious reports
- Right more, or worse
- Marker this vehicle
Where 2009 sits in the model line
High risk for a 2009 — 78th riskiest of the 295 2009 vehicles we can rate. Every score on this site is a rank inside its own model year, which is what makes a 2004 and a 2019 comparable at all.
Across the 9 model years of this car that carry enough reports to score, 2008 comes out best at 72 and 2016 worst at 81, with 2009 itself at 73.
No other year of this model scores meaningfully better than 2009, so if this generation is what you want, the year is not the lever.
Within the 2008–2013 generation specifically, 2008 is the strongest year at 72 and 2013 the weakest at 75.
Scores compare each year against other cars of the same model year, so a low number on an older car is a real result and not an artefact of age.
Shorter is better. Years with too few reports to score are shown without a bar rather than as a zero, because no data is not good news.
Within the 2008-2013 generation, 2008 Mercedes Benz C300 scores best at 72 and 2013 Mercedes Benz C300 worst at 75.
Where to spend the inspection money
The mileages below are where the first quarter of reports for each mode had already been filed, which makes them the point at which a fault is worth looking for rather than the point at which it happens: headlight failure or clouding from about 24k, overheating from about 36k, wiring harness or short circuit from about 46k and steering column or shaft failure from about 49k.
On a 2009 Mercedes Benz C300 with more miles than that on it, the useful question to put to a seller or a mechanic is whether headlight failure or clouding has been dealt with, and if so with what parts and at whose expense. A car that has already had the repair is in a different position from one that has not.
None of this is a diagnosis. It is a list of what other owners of the same model year reported, ordered by when they reported it, which is a good place to point an inspection and a poor place to stop.
The limits of complaint data
846 owner reports; fleet size estimated from this year's own recall paperwork. Every count on this page is therefore a floor: it is the number of owners who went to the trouble of filing with a federal agency, which is a small and self-selected fraction of the owners who had the fault.
Of those 846 reports, 560 carried an odometer reading, so the mileages here describe 66% of the sample rather than all of it. Owners also round: readings pile up on multiples of ten thousand, which is why this site publishes "about 90,000 miles" and not "91,438".
Named failure modes come from matching phrases in the complaint text, so a badly worded complaint can land in the wrong bucket. The effect washes out across hundreds of reports and does not wash out across five.
And nothing here predicts what one car will do. These are other people's complaints, filed years apart, on cars maintained by strangers. Read the page as a map of where this model year has previously gone wrong, then have the specific car in front of you inspected.
Questions this page answers
What are the most common problems with the 2009 Mercedes Benz C300?
The most-reported failures are airbag inflator rupture (130 reports, median 90,000 miles), no-start or intermittent start failure (117 reports, median 81,000 miles) and other electrical problem (67 reports, median 72,500 miles). Counts come from owner complaints filed with NHTSA, which are voluntary, so they show what owners bothered to report rather than every fault that occurred.
At what mileage do 2009 Mercedes Benz C300 problems start?
Tail light, brake light or signal failure is the earliest failure mode to show up, with a median reported mileage of 57,500 miles and a quarter of reports before 52,500 miles. Across all failure modes on this year, the median report sits at 70,000 miles.
Is the 2009 Mercedes Benz C300 reliable?
It scores 73 out of 100 on our risk index, which is high — 78th riskiest of the 295 2009 vehicles we can rate. The score is a comparison against other 2009 vehicles, not a prediction about any individual car, and it is built from complaint rates, severity and how early failures appear.
Which year of the Mercedes Benz C300 is best?
Within the 2008–2013 generation, 2008 scores best at 72 out of 100 and 2013 worst at 75. Same body, same engines, different luck.
Where this comes from. Every figure above is computed from NHTSA owner complaints and recall records for this exact make, model and year. Complaints are voluntary and self-selected, so treat counts as a floor. The methodology page writes out each formula, and the same numbers are available as JSON.
What breaks at my mileage Compare with another car
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed