PULSCAR ANALYSIS — P0133 (O2 SENSOR CIRCUIT SLOW RESPONSE, BANK 1 SENSOR 1) AND OXYGEN-SENSOR COMPLAINTS IN NHTSA'S PUBLIC FILES PulsCar analysis of NHTSA public data, September 2026. License: CC BY 4.0 Attribution: "PulsCar analysis of NHTSA public data, September 2026." Published alongside https://www.pulscar.io/blog/p0133-code ------------------------------------------------------------------------------ Prepared September 2026. Source data: NHTSA public flat files (complaints received 2015 to 21 September 2026, 780,071 records; manufacturer communications) and documents downloaded from static.nhtsa.gov. 1. Complaints (1,362, all read in full, two readers) Why the pool is wide: only five complaints in the file print P0133, and one of them (ODI 11718543) is a glow-plug code written P133X (and P133A). So the pool is every complaint about an oxygen or air-fuel ratio sensor, with flags for which sensor. First search: every complaint whose narrative names P0133 (a letter O for the zero, a space, hyphen or period after the P, a two-character suffix, or a bare 133/0133 after "code", "codes", "DTC", "DTCs", "error", "CEL" or "coded"), a companion oxygen-sensor code (P0130-P0132, P0134, P0150-P0154, P0139, P0159, P013A-P013F, P014A-P014F, P015A-P015D, P2A00, P2A03, P2195-P2198, P1133, P1153), or oxygen-sensor wording ("O2 sensor", "02 sensor", "oxygen sensor", "A/F sensor", "air fuel ratio sensor", "lambda sensor", "HO2S"): 1,260 complaints (5 name P0133, 73 a companion code, 1,209 the wording; a complaint can match more than one). Completeness audit: before writing, an independent audit searched the same file for what the first search missed — misspellings ("O2 censor", "oxygen senor"), sensors named without O2 wording ("upstream sensor", "downstream sensor", "catalytic converter sensor" on a gasoline engine) and other oxygen-sensor codes (heater and downstream codes, codes written without the P) — and 102 more were added. The found_by column says which search found each complaint. Coding: the codebook (codebook.txt) was written, dated and hashed before any complaint was read, and an addendum for the 102 added complaints was hashed before they were read. Two independent classification passes coded all 1,362 separately, each from the codebook only, without seeing the other's codes, each seeing only the codebook and its batch of complaints. One category (N not an oxygen-sensor fault on the owner's vehicle; E engine: oil use, coolant, internal damage; F fuel, air or ignition; X catalytic converter or exhaust; W wiring, fuse, relay or connector; M computer or software; S the sensor alone; U no repair or cause named) and four flags (upstream, downstream, drivability, returned_after_repair). Agreement: category 1,157 of 1,362 (84.9%), Cohen's kappa 0.815; upstream 0.910; downstream 0.880; drivability 0.959; returned_after_repair 0.918. Every disagreement (300 decisions) was read in full and settled under written rules R1-R16 (codebook.txt), and a consistency pass corrected 50 agreed codes that contradicted those rules; the rule_applied column records both. Final: not an oxygen-sensor fault (N) 59; of the 1,303 relevant: the sensor alone (S) 447, the engine (E) 237, no repair named (U) 227, converter or exhaust (X) 156, fuel, air or ignition (F) 146, wiring (W) 55, computer or software (M) 35. Upstream 229, downstream 163, both 96; drivability 706; returned after a repair 578 (S 260, E 96, F 96, X 73, M 25, U 15, W 13). Four relevant complaints name P0133 (ODI 11362939, 11415689, 11513767, 11635988). Makes among the 1,303: Ford 218, Chevrolet 197, Kia 116, Jeep 88, Nissan 84, Hyundai 79, Toyota 68, Dodge 65, Honda 53, GMC 43, and others. Models: Equinox 53, Soul 49, Focus 38, Escape 37, Altima 36, F-150 33, Cruze 30, Terrain 28. Median model year 2013; median reported mileage 97,000 (741 complaints give a mileage from 1,000 to 400,000). By year received: 2015 117, 2016 72, 2017 83, 2018 102, 2019 142, 2020 120, 2021 101, 2022 92, 2023 126, 2024 124, 2025 128, 2026 (to 21 September) 96. Mention counts (by script, not coded; case-insensitive whole words in the relevant narratives): oil 263 (129 in E), coolant 65 (37 in E), rodent, rat, mice, mouse or squirrel 11 (10 in W). Figures count complaints, not vehicles. 2. Owner-reported amounts (219 figures in 166 complaints) Every dollar figure in the relevant complaints for a diagnosis, a sensor, wiring, software, fuel, air or ignition work, a converter or exhaust, an engine, or several of these together, whether paid, billed or quoted; excluded (180 numbers, listed with reasons in our working files): mileages and other numbers that are not prices, vehicle prices, refunds and loan balances, towing and rentals, repairs unrelated to the oxygen-sensor fault (transmissions, steering, seat belts and others), figures already inside a stated total, and totals that mix unrelated work. 101 figures are quotes, 71 described as paid, 39 billed, 8 not stated. Each figure was checked by script against the narrative and sorted into one group by the repair the narrative ties it to (group column). 3. Manufacturer documents (784 distinct, read) First search: every manufacturer communication whose NHTSA index summary names P0133, a companion code or oxygen-sensor slow-response wording (482 records). Completeness audit: an independent audit widened the search (other oxygen-sensor codes, oxygen-sensor wording in summaries, extended warranties, maker-specific codes) and added 442 records. After removing 127 byte-identical copies (md5) and 13 records with no PDF on NHTSA, 784 distinct documents were read: 388 from the first search, 396 from the audit. Near-identical revisions (5-word shingle Jaccard 0.6 or more) were read sentence by sentence against a copy read in full; page images were read where the text layer was empty or scrambled. Of the 784: 90 direct, 119 list P0133 or a sensor-1 slow-response code among others, 551 related, 24 not relevant. 141 print P0133 in their own text (as P0133, P013300, P0133:00 or P0133-00); two Ford bulletins with scrambled text layers (24-2036, 24-2066) were read from page images and are counted among them. By script over the 139 with a readable text layer: 86 mention reprogramming, flashing, software or calibration, 28 mention replacing an oxygen or air-fuel sensor (22 of those together with software), and 29 are Volkswagen on-car analysis lists that print no fix; the two Ford bulletins are reprograms. Every verbatim quote in the article was checked by script against the document or complaint text; the one quote from an image-only page was checked against a transcription of the page image. Coverage status in September 2026 is our computation from the terms printed in each document, not a statement by the manufacturer. Limits: complaints over-represent drivability problems and expensive repairs; owners report the diagnosis as they understood it; most complaints do not say which sensor, so the category counts describe the oxygen-sensor family, not P0133 alone; searches of NHTSA's index cannot see bulletins whose summary is blank or codes that appear only inside a PDF. Nothing here is a failure rate. Relevance of 13 documents whose extraction entry did not state it (Stellantis flashes and GM PIP5468 files that list P0133 or P2A00 among other codes) was set to "listed".