PULSCAR ANALYSIS - P0130 AND P0131 (OXYGEN / AIR-FUEL SENSOR CIRCUIT, BANK 1 SENSOR 1) AND SISTER CODES 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/p0130-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 and nhtsa.gov. Every number in the article that is not a quotation comes from these files or from a stated computation. 1. Complaints (1,355) First search (1,277): every complaint whose narrative names P0130, P0131, P0132, P0133 or P0134 by any spelling we searched (a letter O for zero, a space, hyphen or period after the P, the suffix 00, or a bare 130 to 134 after "code", "DTC", "error", "CEL", "coded" or "fault"), a bank 2 code (P0150 to P0154), another oxygen-sensor code (P0135 to P0160, P2195 to P2198, P2A00 to P2A03), or the words oxygen sensor, O2 sensor, 02 sensor, lambda sensor, air-fuel sensor, A/F sensor, wide-band sensor, HO2S, heated oxygen or upstream sensor. Nothing was sampled: every narrative the searches returned was sorted. The text searches are written out in codebook.txt. Second search (78): an independent search of the same file for what the first one missed (misspellings such as "oxygen censor" and "oxygen senor", maker names such as HEGO and H02S, "catalytic converter sensor", "exhaust sensor", codes written without the P), run after the first batch was sorted; every complaint it proposed that meets the unchanged relevance rule was added. found_by in the complaints file says which search found each one. Sorting: the sorting rules (codebook.txt) were written, dated and fingerprinted before any complaint was sorted; an addendum for the second batch, which lists the extra spellings, was fingerprinted before that batch was sorted. Every complaint was sorted twice, independently, by the same written rules; each sorting saw the matching excerpt (about 300 characters either side of each matching word) or the whole narrative when nothing matched. Agreement over all 1,355: category 1,112 (82.1%); stall 1,303 (96.2%); nostart 1,335 (98.5%); recall 1,321 (97.5%); returned 1,270 (93.7%). Settling: every disagreement was read and settled by one of the written rules R1 to R10 or the rules added while settling (listed in codebook.txt); the rule applied is in the rule_applied column. A consistency check then re-read the 189 complaints that had been sorted as "sensor replaced" together with "the problem came back" and applied the rule that a part which did not cure the problem does not count as the cause: 138 of those changed category, most of them to "no diagnosis or repair stated" (Rcons1 in codebook.txt). The resolution column says which complaints were changed. Result: 1,273 relevant, 82 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. Only 1 complaint in the whole file prints P0130 and 12 print P0131 (one of them writes 0131 without the letter P): the set describes oxygen-sensor events in the owners' words. 2. Documents (850 index entries that name an oxygen / air-fuel sensor code or use oxygen / air-fuel sensor wording; 389 requested, 385 files with a text, 346 distinct documents) First search: NHTSA's index of manufacturer communications, entries whose summary names P0130 to P0139, P0150 to P0154, P2195 to P2198, P2A00 to P2A03 or similar oxygen-sensor codes, or uses oxygen / air-fuel sensor wording: 850 entries. Entries that only mention the sensor in passing, concern only the downstream (after-catalyst) sensor or other codes with their own pages, readiness-monitor or scan-tool display letters, and heavy-truck, bus and motorcycle papers were set aside by reading each index summary (514 of the entries judged only passing, downstream-only, other-code or out of scope). The remaining 336 were requested. Second search: 53 more entries found by the independent search (papers that describe the sensor without the usual letters, sibling revisions). Of the 389 requested, 385 files have a text (downloaded, or reused from earlier work). 227 representative documents were read in full; 158 further files (revisions, copies and look-alikes of those) were compared with the representative line by line. Papers that were scans were read from page images, and only text that could be checked against the printed page was quoted. No recall filing about a light-vehicle oxygen sensor exists in NHTSA's recall file for these words; the recalls the article cites are owner and dealer letters filed as manufacturer communications. 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): 39 of the 385 files are exact copies, leaving 346 distinct documents. 3. Owner-reported amounts (81 figures in 70 complaints) One written inclusion rule (fixed before the figures were decided): a dollar figure is included when the owner states it as a price, charge, bill, quote or estimate for diagnosing, repairing or replacing an oxygen / air-fuel sensor (one or several, front or rear), its connector or wiring, an exhaust-leak repair tied to the sensor complaint, or the catalytic converter when the narrative ties it to the oxygen-sensor event, or the part price of one of these, on that vehicle. Excluded: mileage written as "NNk"; vehicle prices, values, payments, trade-ins, buybacks, refund demands and settlement sums; engine, head gasket, turbo, transmission, fuel pump, computer and brake repairs; totals that mix sensor work with other major work unless the owner attributes the figure to the sensor repair; restatements; other owners' costs; rental-car costs; figures not tied to the sensor event. Status comes from the owner's own words (paid, billed, quoted, not stated); group is sensor, wiring, exhaust, converter, mixed, diag or monitor (one repair quote for an emissions monitor that would not set). 353 candidate figures were excluded; the reason for each is in p0130-excluded-figures.csv. 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 describe the complaints, not all cars. The document set holds what NHTSA's index lists; a maker paper that is not in the index is not in it. Motorcycles, powersports, motorhome chassis, buses and Class 7-8 trucks were not looked for; four such vehicles (two motorcycles, a Class 8 tractor and a Class C motorhome) are among the 1,273 that describe a fault and are counted; a third motorcycle and a second motorhome are in the 1,355 and were filed as not describing an oxygen-sensor fault. Most complaints do not say whether the front or the rear sensor is meant, so the set describes oxygen-sensor events in general, not only bank 1 sensor 1. Category agreement between the two sortings is lower than for the yes/no questions; that is why every disagreement was settled by a written rule and why the article reports the share of complaints where no cause was stated.