Hyundai Sonata — NHTSA complaint, recall and bulletin analysis PulsCar analysis of NHTSA public data, September 2026 License: CC BY 4.0 ------------------------------------------------------------------ SOURCE FILES ------------------------------------------------------------------ NHTSA Office of Defects Investigation public flat files, downloaded and loaded into a local SQLite database: - COMPLAINTS: 777,040 owner complaints received 1 January 2015 through 8 September 2026 (the ODI complaint flat file; "received" is the date NHTSA logged the report, not the date of failure). - RECALLS (RCL flat file): one row per make/model/model-year per campaign. Campaign counts below are DISTINCT campaign numbers. - MANUFACTURER COMMUNICATIONS (TSB flat file): one row per make/model/model-year per document. Document counts are DISTINCT NHTSA document IDs. All queries were run 18 September 2026. ------------------------------------------------------------------ BASE SET ------------------------------------------------------------------ SELECT * FROM complaints WHERE make='HYUNDAI' AND model='SONATA'; -> 11,544 complaints. This is every Sonata complaint in the file, all model years (1999-2026), including Sonata Hybrid rows where NHTSA recorded the model as SONATA. The ODI file does not carry a trim or engine field, so this set cannot be split by engine (Theta II versus other) from the data alone. All-complaint baselines used for comparison, computed over the whole 777,040-row file: towed 5.11% crash 4.37% fire 1.82% Sonata, whole set: towed 6.92%, crash 3.57%, fire 3.99%, 374 injuries, 9 deaths. Mileage: rows with miles <= 0 or >= 400,000 are dropped before any median or quartile. 6,356 of 11,544 Sonata rows carry a usable mileage. Median 83,000; first quartile 54,000; third quartile 116,000. ------------------------------------------------------------------ THE ENGINE-FAILURE SET (1,637 complaints) ------------------------------------------------------------------ Selection (Python re, case-insensitive, over the complaint narrative): FAILURE WORDS: \b(knock\w*|rod bearing|seiz\w+|engine (?:blew|blown|failed|failure| died|replaced|stopped|shut down))\b AND ENGINE CONTEXT: engine|motor|oil press|rod bearing|short block|theta|p1326|connecting rod AND NOT (a knock word sitting next to a chassis word, unless NHTSA also filed the complaint under the ENGINE component): knock\w*[^.]{0,60}(steering|suspension|strut|wheel|coil spring|door|dash) | (steering|suspension|strut|front end|coil spring)[^.]{0,60}knock SAMPLE READING (required before publishing any keyword count): - First, loose version (failure words only): 1,823 matches. 30 random matches were read in full. Three were not engine failures at all — a fractured front coil spring described as "knocking and grinding", a steering-column "clicking and knocking" noise, and a loose steering column — a measured false-positive rate of 10% (3/30). - The engine-context requirement and the chassis exclusion above were added in response. 30 fresh random matches from the tightened set (1,637) were read in full: 0 were non-engine. One borderline row described engine knocking together with bad struts; it names the engine, so it was kept. - A 0/30 reading does not mean the false-positive rate is zero. It means it is small enough that 30 reads did not find one. Treat the figures as approximate. Outcome of the engine set: towed 11.73% (baseline 5.11%) fire 3.60% (baseline 1.82%) crash 1.22% (baseline 4.37%) 15 injuries, 0 deaths median mileage 93,000 over 811 rows with usable mileage ------------------------------------------------------------------ "WHAT OWNERS SAY" CATEGORIES ------------------------------------------------------------------ Each category is a regular expression run over the 1,637 narratives. The categories OVERLAP — one complaint can be counted in several — so the shares do not sum to 100%. They measure the VOCABULARY of the file, not the frequency of repairs: a complaint that does not use a word is not evidence the thing did not happen. engine replaced / short block replaced engine (was |been |has been )?(replac|swap)|new engine| short block (was )?replac|replaced the engine coverage denied, refused or paid out of pocket denied|refus\w+|declin\w+|not cover|would not cover|won't cover| wouldn't cover|out of (pocket|warranty) KSDS or knock-sensor campaign named knock sensor detection|ksds|campaign ?95[0-9]|campaign ?96[0-9]| knock sensor (software|update|recall) DTC P1326 quoted p ?1326 limp mode / reduced power limp (home )?mode|reduced power|limp-home| engine protection mode oil consumption named burn\w* oil|oil consumption|adding (a )?quart| low on oil stall while driving (stall\w*|shut (off|down)|cut off|died) (while |when )?(driving|on the (highway| interstate|freeway)|in traffic) | while driving[^.]{0,40}(stall|shut off|shut down|died) fire or smoke caught fire|on fire|flames| smoke (came|from|pouring)|engine fire recall/settlement named recall|settlement|class action| warranty extension|extended warranty KNOWN LIMITATION on the "denied" category: the words also appear when an owner writes that a dealer refused a LOANER, or that a previous owner was refused. The category is therefore an upper bound on coverage refusal. 20 random matches were read; 16 concerned engine repair coverage. The other 4 were a refused loaner, an out-of-warranty steering repair, a passenger who refused to ride in the car, and an owner who refused to pay a bill — roughly one in five. The by-generation comparison below is between groups measured the same way, so the comparison survives the noise even though the level does not. ------------------------------------------------------------------ BY-GENERATION COMPARISON ------------------------------------------------------------------ Generations are model-year buckets tied to the documented programs: 2011-2012 (YF) -> NHTSA recall 15V-568 586 engine-set complaints 2013-2014 (YF) -> NHTSA recall 17V-226 424 2015-2019 (LF) -> no Sonata engine RECALL; covered by Hyundai bulletins 21-01-002H / 22-EM-001H only 558 2020+ (DN8) -> outside the Theta II programs 15 2010 and older -> outside the Theta II programs 54 Denial language: 20.1% (2011-2012), 17.5% (2013-2014), 26.7% (2015-2019). This is a difference in how owners WRITE about their claims, not a measured refusal rate, and 2020+ (15 complaints) is too small to read. ------------------------------------------------------------------ THE STEERING SET ------------------------------------------------------------------ Complaints whose components field contains STEERING: 1,794 (15.4% of the Sonata file), of which 832 are model year 2011 alone. Within the 832: 45.3% use a click/knock/clunk word; 3.6% describe a loss of power steering or assist; 4.6% name EPS or a steering warning light; 10.0% mention a crash or near-crash; 39.9% name a recall. Median mileage 80,000 over 652 rows. Towed 1.68%, crash 1.68%. Received-year distribution for those 832: 2015=187, 2016=320, 2017=122, 2018=73, 2019=52, 2020=34, 2021=16, 2022=7, 2023=12, 2024=3, 2025=1, 2026=5. NHTSA recall 16V-190 (EPS control unit) was filed 5 April 2016. The 2015 figure is a floor, not a count: the complaint file itself begins on 1 January 2015, so complaints filed before that date are not in it and no pre-recall trend can be measured from this data. ------------------------------------------------------------------ CATALYTIC CONVERTER THEFT — AN HONEST NEGATIVE ------------------------------------------------------------------ Theft words (theft|stolen|steal) appear in 45 of 11,544 Sonata complaints (0.39%). Exactly ONE of those 45 names a catalytic converter. "Catalytic converter" appears anywhere in 29 complaints. This measures the ODI complaint file, which is a safety-defect channel and not a theft register; owners have no reason to report a theft to NHTSA. It is therefore evidence that this dataset cannot support a converter-theft claim about the Sonata — not evidence that such thefts do not happen. The article says exactly that, and makes no frequency claim. ------------------------------------------------------------------ RECALL AND BULLETIN COUNTS ------------------------------------------------------------------ Distinct recall campaigns naming a Sonata: 43 (published in sonata-recall-campaigns.csv with populations and filing dates). Distinct manufacturer communications naming a Sonata: 567. Primary documents opened and read for the article (all fetched 18 September 2026, HTTP 200): Hyundai TSB 22-EM-001H (Jan 2022), NHTSA 10207811 — Limited Lifetime Warranty, engine long block, connecting-rod bearing wear Hyundai TSB 22-EM-001H-1 (May 2022), NHTSA 10211673 — same, revised Hyundai TSB 21-01-002H (Jan 2021), NHTSA 10186818 — 10 years/120,000 miles, superseded by the above Hyundai TSB 21-EM-004H (Mar 2021), NHTSA 10190044 — Bearing Clearance Test service procedure Hyundai TSB 19-01-002H-1 (Mar 2019), NHTSA 10154674 — KSDS campaign Hyundai TSB 20-ST-003H (Aug 2020), NHTSA 10179246 — C-MDPS worm shaft bearing noise Hyundai TSB 23-01-014H-3 (Apr 2023), NHTSA 10235341 — Service Campaign 993, IBU/BCM anti-theft software and decals Recall records 10V-426, 15V-568, 16V-190, 17V-226, 18V-934, 20V-121, 22V-312, 23V-526, 25V-796 as filed in the RCL flat file. ------------------------------------------------------------------ LIMITATIONS ------------------------------------------------------------------ 1. Complaints are self-reported, unverified, and not normalized by how many vehicles are on the road. They are NOT failure rates. A model with more complaints is not "less reliable" than one with fewer. 2. Counts are shaped by publicity. A recall, a settlement or a news story causes owners to file, so a spike in a model year can measure attention rather than failures. 3. The file starts 1 January 2015. Nothing here can describe the period before that date, and the 2015 bucket is a partial view of everything that happened earlier. 4. Mileage is entered by the owner and is missing on 45% of Sonata rows. 5. Model-year buckets are the owner's statement of the model year, not a VIN decode, and roughly 3 rows carry a placeholder year of 9999. 6. Keyword categories measure words, not events. FILES sonata-complaints-by-model-year.csv sonata-engine-reports-what-owners-say.csv sonata-engine-set-by-generation.csv sonata-recall-campaigns.csv method.txt (this file)