PULSCAR ANALYSIS - P2096 / P2097 (POST-CATALYST FUEL TRIM SYSTEM TOO LEAN / TOO RICH, BANK 1) AND THE FAULTS AROUND IT IN NHTSA'S PUBLIC FILES PulsCar analysis of NHTSA public data, October 2026. License: CC BY 4.0 Attribution: "PulsCar analysis of NHTSA public data, October 2026." Published alongside https://www.pulscar.io/blog/p2096-code ------------------------------------------------------------------------------ Prepared October 2026. Source data: NHTSA public flat files (complaints received 1 January 2015 to 4 October 2026 - the latest received date in the files; manufacturer communications; recalls since 2010) and documents downloaded one at a time from static.nhtsa.gov. 1. Complaints (830) Why the set is wider than the code: only a few dozen owners print P2096 or P2097 in their complaint (the exact counts are in the article and can be recomputed from the complaints file). The searches therefore also took the wording owners use for the same fault. First search (493): every complaint whose narrative names P2096 or P2097 by any spelling we searched (a letter O for zero, a space, hyphen or period after the P, the suffix 00, or a bare number after "code", "DTC", "error", "CEL", "coded" or "fault"), or a bank-2 sister code P2098 or P2099 in the same spellings, or names the sensor behind the catalytic converter in owners' words (post-catalyst, downstream, rear or second oxygen sensor, bank 1 sensor 2), or names fuel trim or a lean / rich condition, or names an oxygen sensor together with a catalytic converter, each of the last three together with a word about a check-engine light, a code or an emissions fault. The exact text searches are in codebook.txt. Second search (337): an independent search of the whole file for what the first one missed, run after the first batch was sorted. It proposed 943 further complaints; 337 were added (fuel-trim codes P0171, P0172, P0174 and P0175 in other spellings, lean / rich diagnoses without a converter word, the rear sensor named in other words, oxygen-sensor circuit codes, bare numbers after a code word) and 606 were not (578 describe an oxygen sensor replaced or blamed with a check-engine light but name neither the rear sensor, a fuel-trim code nor a catalytic converter; 28 are air-fuel-ratio-imbalance codes, which are injector or purge-valve events). found_by in the complaints file says which search found each complaint. Sorting: the sorting rules (codebook.txt) were written, dated and fingerprinted before any complaint was sorted; an addendum for the second batch was fingerprinted before that batch was sorted. Every complaint was sorted twice, independently, by the same written rules, each time from the rules alone, without sight of the other sorting. One category (N not an oxygen-sensor or fuel-trim event on this vehicle; S rear sensor replaced; Z oxygen sensor replaced, position not given; C catalytic converter; X exhaust leak; F fuel or air metering; W wiring or power; P software or a campaign procedure only; O another cause; K checked and cleared; U nothing found or done stated) and four yes/no flags (stall, inspection, recall, returned) were recorded for each. Agreement over all 830: category 735 (88.6%); stall 791 (95.3%); inspection 828 (99.8%); recall 801 (96.5%); returned 793 (95.5%). Settling: every disagreement was read and settled by one of the written rules R1 to R12 (listed in codebook.txt); the rule applied is in the rule_applied column. A consistency check then applied R12 to every complaint on which both sortings had agreed and whose only match was an air-fuel-imbalance code: 66 rows moved to N (resolution says "changed in consistency pass"). Result: 703 relevant, 127 not relevant. Counts are counts of complaints, not cars. A complaint is evidence that an owner wrote to NHTSA; nothing here is a failure rate. 2. Documents (477 index entries, 471 files with a text, 410 distinct documents) First search: NHTSA's index of manufacturer communications, entries whose summary names P2096, P2097, P2098 or P2099, or names post-catalyst or downstream oxygen-sensor or fuel-trim wording with a word about a fault, a repair or a software update: 281 entries were taken for reading. Second search: 196 more entries found by the independent search (the rear / downstream oxygen-sensor class, and the lean / rich class where the file was already on disk); the other index entries it found by summary alone (670 further bulletins, mostly front oxygen-sensor and lean / rich bulletins that belong to other pages) were not read. 6 entries have no file on NHTSA. Reading: 288 documents were read in full; 183 further files (revisions, copies and look-alikes of those) were compared with the one read in full, line by line. Seven papers whose pages are images were transcribed from the images before reading, and eight others whose printed text could not be read were read from images of their pages. Every verbatim quotation in the article was checked against the text of the named document or complaint. Model years, engines, build dates and coverage terms are as printed in the documents, never taken from NHTSA's index, which expands years. Coverage status "as of September 2026" is the authors' computation from printed terms. duplicate_of marks exact copies (same text as another file): 61 of the 471 files are exact copies, leaving 410 distinct documents. 3. Owner-reported amounts (82 figures) One written inclusion rule (RULE below, fixed before the figures were decided): a dollar figure is included when the owner states it as a price, charge, bill or quote for diagnosing, repairing or replacing a part or doing a job that the narrative ties to the oxygen-sensor, fuel-trim or lean / rich fault on that vehicle (a rear or front oxygen sensor, the catalytic converter replaced for it, an exhaust leak, a fuel or air-path part, wiring), or a diagnostic fee for it, or the part price of such a part. Excluded: mileage written as "NNk"; vehicle, loan, lease, insurance and trade-in values; towing and rental; other systems; totals that mix this fault with other major work unless the owner attributes the figure to this fault's repair; restatements, the upper end of a range counted in one row, and the same text filed twice; goodwill and reimbursement amounts; general statements about other owners. 127 figures were excluded, each with a reason (amounts exclusions). Status comes from the owner's own words (paid, billed, quoted); group is sensor, converter, exhaust, fuel, wiring, diag, mixed or other; a range is one row with the low end in amount_usd and the high end in amount_high_usd. 4. Limits The complaint file holds the cases where an owner wrote to NHTSA, in the owner's words, with no verification; owners whose trouble ended are mostly not in it. The shares reported (for example how many sensor replacements were followed by a return of the problem) describe the complaints, not all cars. Honda owners writing about fuel injectors and rich-running codes make up a large part of the fuel and air category because many of them name a rich or fuel-trim code; they are not owners of P2096 itself. The document set holds what NHTSA's index lists and what the searches found; a maker paper that is not in the index is not in it. Motorcycles, powersports and heavy trucks are outside the study and are sorted N. RULE for dollar figures: One inclusion rule for dollar figures (written before deciding any) INCLUDE a dollar figure when the owner states it as a price, charge, bill or quote for diagnosing, repairing or replacing a part or doing a job that the narrative ties to the oxygen-sensor / fuel-trim / lean-rich fault on THIS vehicle (a rear or front oxygen sensor, the catalytic converter replaced for it, an exhaust leak, a fuel or air-path part such as injectors, MAF, intake manifold, PCV or purge valve, wiring), or a diagnostic fee for it, or the part price of such a part. EXCLUDE: mileage written as 'NNk'; vehicle price, loan, lease, insurance or trade-in values; towing and rental; repairs of other systems (engine replacement, transmission, brakes, A/C, clutch, turbo, electrical); totals that mix this fault's work with other major work unless the narrative attributes the figure to this fault's repair; a figure already counted in the same narrative (restatement, or the upper end of a range counted in one row); the same owner text filed twice; goodwill or reimbursement amounts; figures about other owners or general statements ("costs about"). STATUS (from the owner's own words): paid (paid / spent / incurred / out of pocket), billed (bill, charged, cost), quoted (told, quoted, wants, estimated, would cost, recommended), not stated. GROUP: sensor (oxygen / air-fuel sensor), converter, exhaust (leak, pipe, manifold), fuel (injectors, fuel pump, MAF, intake path, PCV, purge valve), wiring, diag (diagnostic fee), mixed (several of these in one price), other. A range is one row: amount_usd is the low end, amount_high_usd the high end.