Other engine problem on the 2009 Hyundai Sonata
1 crash 3 fires 2 injuries 6 of the 40 reports for this failure mention a crash, a fire, an injury or a death. Those are the owner's words on the complaint form, not a verified finding, and one report can mention more than one.
When other engine problem gets reported
Owners of the 2009 Hyundai Sonata report other engine problem at a median of 100,000 miles. A quarter of the reports come in before 72,500 miles and a quarter after 135,000 miles, from 34 reports that carried an odometer reading.
A part like this is normally expected to survive 95,000 miles. It is the 3rd most-reported problem on this model year.
The mileage distribution
The reported range runs from 32,500 miles at the tenth percentile to 152,500 miles at the ninetieth, a spread of 119,900 miles across the middle 80% of reports.
A spread this wide points at use rather than design. Towing, climate, service history and city mileage all move a failure like this, so the median is a weak guide to any individual car.
15% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 31,500 miles | 73,500 miles | 100,500 miles | 133,750 miles | 151,400 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Of these reports, 1 a crash, 3 a fire and 2 an injury are mentioned. Owners write their own complaints and the agency does not verify them, so read this as what the reports say happened rather than as a confirmed count.
Putting it right typically runs $300–$4,000 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 26 model years of this car. It shows up earliest on the 2023, at a median of 100 miles, and latest on the 2008 at 115,000 miles.
By volume the 2011 carries the most reports, with 596; the 2009 has 40. A mode that appears across most years of a model is usually a design choice rather than a bad batch.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
Purchased a 2009 sonata in spetember of 2008, the air conditioner does not drain and has developed a mold smell when air is on. Returned to dealer, they want to "clean" evaporator with a foam cleaner at a cost of over $100.00. The tech said to drive car in the outside air circulator and not the recycle air engaged, since I refused the "cleansing". This making me sick, friend has a 2009 santa fe with same issue. *tr
1) was making a right turn into a parking lot. There was a slight incline. There was a quarter of a tank of gas in the car. 2) the engine appeared to turn off, however the electronics never turned off. Power steering was no longer available once the engine stopped running. 3) I attempted to restart the car, but it wouldn't start. You could hear the engine trying to start. I placed the car in neutral and pushed it into a parking space. About 5 minutes later I successfully restarted the car. I had the car towed to the dealership and they could not diagnose the problem or detect that anything had occurred. *tr
Tl* the contact owns a 2009 hyundai sonata. The contact stated that while driving 65 MPH, the vehicle stalled twice. The vehicle was merged to the shoulder with the engine off for approximately 35 minutes before it was able to be restarted. There were no warning lights illuminated. The vehicle was taken to the dealer who inspected and test drove the vehicle but could not locate the problem. The manufacturer was notified and a claim was filed. The manufacturer advised that a representative would be calling within 24 hours. The failure mileage was 18,941.
Also reported on the 2009 Hyundai Sonata
Other brake problem
Other body or interior problem
Other electrical problem
Other driver assistance problem
Other powertrain problem
Premature brake pad or rotor wear
How far this goes
Complaints are voluntary, so 40 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does other engine problem happen on the 2009 Hyundai Sonata?
Across 34 owner reports that included an odometer reading, half were filed by 100,000 miles. A quarter were filed before 72,500 miles and a quarter after 135,000 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is other engine problem on the 2009 Hyundai Sonata?
40 reports have been filed with NHTSA, about 1.1 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
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