PulsCar analysis of NHTSA public data, September 2026 Toyota Corolla: what 6,279 owner complaints and 42 recall campaigns say, and what is missing from them Licensed CC BY 4.0. Queries run 18 September 2026. -------------------------------------------------------------------------- SOURCE FILES -------------------------------------------------------------------------- NHTSA ODI complaint flat files COMPLAINTS_RECEIVED_2015-2019, _2020-2024, _2025-2026 https://static.nhtsa.gov/odi/ffdd/cmpl/ (field dictionary: CMPL.txt) 777,040 distinct vehicle complaints (ODINO, product type V) received 1 January 2015 to 8 September 2026. Of those, 6,279 name MAKE = TOYOTA and MODEL = COROLLA. IMPORTANT SCOPE NOTE: the flat file treats each body style as its own model. COROLLA MATRIX (327 complaints), COROLLA CROSS (306), COROLLA IM (20), COROLLA CROSS HYBRID (10), COROLLA HATCHBACK (6) and COROLLA HYBRID (5) are NOT included in the 6,279 anywhere in this analysis. Where the article discusses the Matrix or the hatchback it says so and uses recall and bulletin documents, not these counts. NHTSA recall flat file FLAT_RCL.zip. Campaign details were re-read live on 18 September 2026 from https://api.nhtsa.gov/recalls/campaignNumber?campaignNumber= NHTSA manufacturer communication flat files TSBS_RECEIVED_2015-2019, _2020-2024, _2025-2026 https://static.nhtsa.gov/odi/ffdd/tsbs/ (field dictionary: TSBS.txt) NHTSA investigation flat file FLAT_INV.zip. -------------------------------------------------------------------------- A MEASUREMENT PROBLEM THAT HAD TO BE FIXED FIRST -------------------------------------------------------------------------- NHTSA changed how it stores complaint narratives during 2021. Measured share of narratives that are entirely upper case, by year received: 2015-2020 about 100%; 2021 44.1%; 2022 2.1%; 2023 1.5%; 2024 1.0%; 2025 1.0%; 2026 0.8%. A keyword regex written in upper case and matched case-sensitively returns a plausible-looking number that silently excludes almost every complaint filed after mid-2021 — which on this vehicle would have hidden the entire coolant bypass valve cluster, all of which arrived from 2023 onwards. EVERY query below is case-insensitive. -------------------------------------------------------------------------- COMPONENT COUNTS -------------------------------------------------------------------------- NHTSA's COMPONENTS field holds one or more component names separated by " | ". A complaint counts once for each distinct component family it names, so family counts sum to more than 6,279. AIR BAGS 3,882 rows; 3,884 complaints contain the string "AIR BAG" in any component (61.9% of the file) UNKNOWN OR OTHER 504 ENGINE 484 ELECTRICAL SYSTEM 394 POWER TRAIN 310 SERVICE BRAKES 279 STEERING 254 VEHICLE SPEED CONTROL 250 STRUCTURE:BODY 187 This is the manufacturer-neutral field NHTSA assigns; it is not the owner's wording. -------------------------------------------------------------------------- MILEAGE AND RATE FIELDS -------------------------------------------------------------------------- Mileage: NHTSA's MILES field, rows with 0 < miles < 400,000 only. All Corolla complaints: 1,998 of 6,279 report a usable mileage. Median 61,000; first quartile 24,900; third quartile 109,000. 33.0% at or under 36,000 miles; 29.2% at or above 100,000. Air-bag subset: 790 usable mileages, median 75,500. All-complaint baseline (whole file): 392,935 usable mileages, median 70,000. NOTE: only 32% of Corolla complaints carry a mileage at all, largely because recall-related filings often have no failure to report. Towed / crash / fire: NHTSA's TOWED, CRASH and FIRE flags, share = Y. All Corolla: towed 7.41%, crash 10.96%, fire 0.57%, 599 injuries, 10 deaths. Air-bag subset: towed 8.11%, crash 12.08%, fire 0.21%, 474 injuries, 5 deaths. Non-air-bag Corolla complaints: towed 6.26%, crash 9.14%, fire 1.17%. All-complaint baseline: towed 5.11%, crash 4.37%, fire 1.82%. The crash share is high because an air-bag complaint is usually filed after a crash, or by an owner who has been told to expect one. It is NOT a statement about how often this vehicle crashes. -------------------------------------------------------------------------- THE AIR-BAG SUBSET (3,884) -------------------------------------------------------------------------- Membership: the COMPONENTS field contains "AIR BAG". No narrative matching is involved, so there is no keyword false-positive rate to report. Phrase shares inside the subset (case-insensitive, full narrative): names a recall, Takata or an inflator ...... 3,254 (83.8%) parts-availability language ................ 1,558 (40.1%) regex: no parts | parts (are|were)? not available | part is not available | no replacement part | backorder | back-order | not available | no remedy | interim | waiting for (the) part | still waiting | been waiting | waiting (since|for) | loaner | rental says an air bag did not deploy .............. 296 (7.6%) Twelve randomly drawn parts-availability matches were read in full; all twelve were genuine reports of a recall repair that could not be scheduled or completed. Much of this language is NHTSA's own intake wording — the phrase "VIN TOOL CONFIRMS PARTS NOT AVAILABLE" appears verbatim in many records — so the count measures how often the agency's own intake recorded an unavailable remedy, which is a narrower and more reliable thing than a free-text keyword count usually is. -------------------------------------------------------------------------- THE COOLANT BYPASS VALVE SUBSET (186) -------------------------------------------------------------------------- Membership, case-insensitive, full narrative: coolant bypass valve | bypass valve | p2681 | engine maintenance required 165 match one of the first three (the part or the code); 21 match only "engine maintenance required". All 21 of those were read in full and all 21 describe the same failure, so the loose term is kept. By model year: 2019 = 22, 2020 = 118, 2021 = 36, 2022 = 8, 2023 = 1, 2024 = 1. By year received: 2022 = 1, 2023 = 7, 2024 = 117, 2025 = 44, 2026 = 17. Phrase shares: mentions overheating 20; mentions the A/C 16; mentions a coolant leak 17; mentions a recall, warranty or being out of warranty 33. Owner-reported dollar figures: every $N with 50 <= N <= 10,000 in the subset. 59 figures inside 38 of the 186 complaints. Median $745; first quartile $331; third quartile $890; largest $2,800. THIS IS NOT A PRICE. Owners who write a number are the ones who paid one, and a single complaint can contribute a quote and an invoice. Only 8 mileages are usable in this subset, which is too few to publish a median; the article quotes individual owner mileages only where the narrative states them. -------------------------------------------------------------------------- THE SUBSETS THAT ARE SMALL, AND WHY THAT IS A FINDING -------------------------------------------------------------------------- excessive oil consumption language ......... 26 (0.4%) same regex as the PulsCar Chevrolet Equinox analysis, so the two numbers are directly comparable: 26 here against 812 there. 14 of the 26 are model year 2009. Median mileage 132,500 (16 usable). transmission or CVT plus a slip, shudder, judder, hesitation, jerk, surge or whine word ... 44 (0.7%) catalytic converter mentioned at all ........ 24 (0.4%) catalytic converter described as stolen ...... 0 WHAT THESE ZEROES AND SMALL NUMBERS DO NOT MEAN. NHTSA's complaint file exists for suspected vehicle defects. A theft is a police and insurance matter, so the absence of theft reports is a fact about the database and says nothing whatever about how often Corolla converters are stolen. Every theft figure in the article comes from a named outside source with its date. Likewise, the 2.4-liter 2AZ engine was a minority option in the 2009-2011 Corolla and NHTSA's file records no engine code, so 26 is a count of complaints, not a rate among the cars that had that engine. -------------------------------------------------------------------------- RECALLS -------------------------------------------------------------------------- 42 distinct campaigns name the Toyota Corolla, covering 28,981,185 potentially affected vehicles summed once per campaign. THAT TOTAL IS NOT A COROLLA NUMBER: NHTSA publishes one population per campaign across every make and model in it, and many of these campaigns cover a dozen Toyota and Lexus nameplates. No per-model split exists. The figure is published only to show the scale of the campaigns this nameplate appears in. Movement of complaint counts around a campaign is descriptive only. A recall changes the number of complaints for at least three reasons that cannot be separated here: the remedy works, owners stop filing because the problem is now official, and publicity briefly makes owners file more. -------------------------------------------------------------------------- DOCUMENTS READ -------------------------------------------------------------------------- Where the article quotes a bulletin, the words come from NHTSA's own summary record of the manufacturer communication, which is NHTSA's paraphrase, and the article says so. No scanned PDF was available for any of these: the static.nhtsa.gov path for a manufacturer communication is not derivable from its document ID. 11012726 / 11012734 / 11012725 / 11012750 Customer Support Program 24TE04, 9 January 2025, "Coverage for Flow Shut-off Valve Coolant Leak", certain 2020-2021 Corolla and certain 2019-2021 Corolla Hatchback among ten Toyota nameplates. The NHTSA record states the base warranty on the valve (36 months or 36,000 miles) but does NOT state the extended term, so the article does not state one either. 11012723 / 11012733 / 11012752 Lexus Customer Support Program 24LE01 and 24LE02, same valve, 9 January 2025. 11020668 T-SB-0112-24 Rev2, 10 July 2025 (first issued 9 January 2025 as 11012731, revised 12 February 2025 as 11014174): 2018-2021 Toyota vehicles with A25A-FKS, A25A-FXS or M20A-FKS engines, "Engine Maintenance Required" in the multi-information display with DTC P268111 or P268115. 10111382 Warranty Enhancement Program ZE7 dealer letter (already cited in the article). 10091611 Warranty Policy Bulletin POL14-12, ZE7 Phase 2. 10091971 ZE7 Phase 2 warranty text: "the engine is covered under the Toyota New Vehicle Limited Warranty for 5 years from the date of first use or 60,000 miles (whichever occurs first)." -------------------------------------------------------------------------- INVESTIGATIONS -------------------------------------------------------------------------- PE14-016 opened 11 Jun 2014, closed 2 Mar 2015, "Air Bag Inflator Rupture" EA15-001 opened 24 Feb 2015, still open in the file, "Air Bag Inflator Rupture" — the action number carried by campaigns 16V-340 and 19V-741 EA19-001 opened 19 Apr 2019, closed 19 Sep 2024, "Electrical overstress", air bag control module — the action number carried by 20V-024 EA21-002 opened 17 Sep 2021, still open, "Desiccated Air Bag Inflator Rupture" PE09-054 / EA10-006 engine stalling, 2005-2008, closed 2010 PE10-008 opened 18 Feb 2010, closed 4 May 2011, "Steering Wander or Drift" DP14-003 opened 19 Sep 2014, closed 29 Apr 2015, "Low-speed surging" -------------------------------------------------------------------------- LIMITATIONS -- READ BEFORE QUOTING ANY NUMBER -------------------------------------------------------------------------- 1. Complaints are self-reported, unverified and voluntary. They are not failure rates and cannot be turned into one, because NHTSA publishes no denominator. 2. Counts follow attention. A recall with a mailed letter produces complaints; a quiet wear item does not. The Corolla file is the clearest example of this in the whole series: four fifths of the complaints filed in 2015-2017 are about one recall campaign family. 3. The complaint file records no engine code, no transmission type and no trim. Every engine-specific statement in the article rests on a document, not on these counts. 4. Mileage, towed, crash and fire are the owner's own entries. 5. Model year in the complaint file is the owner's entry and is sometimes wrong; three complaints carry model year 9999. -------------------------------------------------------------------------- FILES -------------------------------------------------------------------------- complaints-by-model-year.csv model_year, corolla_complaints, air_bag_component_n, air_bag_pct, engine_component_n, engine_pct, mileages_reported, median_miles. airbag-complaints-by-filing-year.csv year_complaint_received, corolla_complaints, air_bag_complaints, pct, naming_a_recall_takata_or_inflator, using_parts_not_available_language. coolant-bypass-valve-complaints.csv model_year, complaints, covered_by_customer_support_program_24TE04. recall-campaigns.csv campaign, report_date, component, potentially_affected_whole_campaign, corolla_model_years, consequence. subset-sizes.csv subset, complaints, pct_of_6279. No personal data is published: no VIN, no city, no dealer name, no owner free text beyond short quoted snippets in the article itself.