PULSCAR METHOD — P0137, P0136, P0139 AND P0140 STUDY
Published alongside https://www.pulscar.io/blog/p0137-code
License: CC BY 4.0

DATA
NHTSA public complaint file: 782,908 narratives received 2015-01-01 to 2026-10-04. Manufacturer communications, recalls and
investigations: NHTSA public indexes and the PDF documents they link to, downloaded one at a time through the NHTSA API and
static server, September-October 2026.

COMPLAINT CODING
Pool: 1,291 complaints from three regular-expression searches (codebook.txt), plus 98 added by an independent completeness audit = 1,389.
Coding: one written codebook (relevance N; category E F C X W M S U; flags upstream, downstream, drivability, returned_after_repair),
hashed before coding. Two blind, independent classification passes per complaint, run separately from the same
codebook and the same excerpt file. A seeded random calibration sample of 200 complaints is flagged in the column calibration_sample.
Agreement, main pool (1,091 complaints, five chunks): category 91.4 percent, kappa 0.888; upstream kappa 0.971;
downstream 0.982; drivability 0.954; returned_after_repair 0.924.
Agreement, audit batch (98): category kappa 0.885, downstream 0.846. Calibration sample (two passes, 200): category 0.924.
Adjudication: every disagreement read in full (152 + 14 + 26) and settled under written rules R1-R21 (codebook.txt); a
consistency pass swept agreed codes for contradictions with the rules and changed 22 (reasons in the CSV). Excerpts: narratives up to
1,800 characters were shown in full; longer ones as excerpts around the oxygen-sensor, converter, exhaust and code words.
The CSV carries both coders' original codes and the final code for every complaint.

OWNER-REPORTED AMOUNTS
All dollar mentions in the narratives of relevant complaints were extracted by script (408) and decided one by one under one written
inclusion rule (about a repair, part, diagnosis or tow on this vehicle tied to the oxygen-sensor fault or its outcome; one figure
for one item; running totals excluded). 201 figures in 161 complaints were kept, 207 excluded with a reason (amounts/exclusions).
Status is paid only when the narrative says the owner paid, quoted when a shop or dealer gave an estimate, billed when the narrative
says a bill or charge, offered, or not stated. Nothing here is a failure rate.

DOCUMENTS
Every manufacturer communication whose index summary names a target code, a neighbouring sensor-2 code, or oxygen-sensor wording with
rear/downstream wording, plus an independent audit's additions: 446 ids, 447 PDF files. Byte-identical files detected by md5 (55);
near-duplicates clustered by five-word shingles (Jaccard 0.6) and compared with their representative. Text layers by pdftotext;
image-only PDFs (Ford 15-0072, 15-0078, 24-2036, 24-2066; Mazda SA288) and two Nissan campaign sheets were read from page images by hand.
Every quotation in the article was checked by script against the document text. Coverage status is the author's computation from
the printed terms as of October 2026.
Files: p0137-1389-complaints-read.csv, p0137-owner-reported-amounts.csv, p0137-documents.csv, codebook.txt.