# Codebook — knock sensor complaints (P0325 study)

Written before any complaint in the set was coded. Pool: every NHTSA complaint whose
narrative names a knock sensor code (P0324-P0334, including spellings with a letter O,
a space, a two-character suffix, or a bare number after the word "code") or the words
"knock sensor" (with common misspellings) or "KSDS".

For each complaint record exactly one CATEGORY and three yes/no FLAGS.

## CATEGORY (one letter)

K — Hyundai/Kia knock sensor detection system. The complaint is about the Hyundai/Kia
    "knock sensor detection system" (KSDS) software, the recall or campaign that installs
    it, a P1326 code, or the engine warning that software gives (flashing check engine
    light plus reduced power, often described as the "knock sensor" update or recall).
    Use K for any Hyundai, Kia or Genesis complaint that mentions the KSDS software, the
    knock-sensor software update/recall/campaign, or P1326 — whether or not the engine failed.
    Do NOT use K for a Hyundai/Kia complaint where a physical knock sensor was simply
    diagnosed or replaced and no software/update/recall/P1326 is mentioned (that is S, D or F).

D — Knock sensor replaced, problem remained. A knock sensor (or its harness/connector) was
    replaced, and the same code or symptom came back, or the real cause turned out to be
    something else (engine damage, another sensor, wiring elsewhere). Use D only when the
    replacement AND the return/other cause are both stated.

F — Engine failure, knock sensor mentioned. The main event is internal engine damage or
    failure (rod or bearing knock, seizure, thrown rod, engine replacement recommended or
    done, oil starvation), and a knock sensor or knock sensor code is mentioned (a code
    that set, a shop's first suspicion) — outside the Hyundai/Kia KSDS story (that is K).

S — Sensor or circuit. A knock sensor, its wiring, connector or harness, or a knock sensor
    code (P0324-P0334) is the problem described or diagnosed, and the engine is not
    described as failing. Includes coolant, oil or rodent damage to the sensor or harness,
    and a sensor replaced with no report of the problem returning.

O — Other. The knock sensor is mentioned only in passing (a list of past repairs, a list of
    recalls, an unrelated narrative), or the complaint is about another system.

Precedence when more than one fits: K, then D, then F, then S, then O.

## FLAGS (yes/no)

engine_failed — the engine is described as seized, destroyed, locked up, needing
    replacement, replaced, rebuilt, or having rod/bearing failure. A recommendation or
    quote to replace the engine counts. A noise alone does not.

stall_or_power_loss — the engine stalled/shut off while running, OR went into limp mode /
    reduced power, OR lost acceleration so the driver could not keep up with traffic.

sensor_replaced — a knock sensor (or its harness/connector) was replaced on this vehicle
    according to the complaint.

## Output
One line per complaint, in the order given:
odino,category,engine_failed,stall_or_power_loss,sensor_replaced,note
note = at most 12 words, no commas, saying what drove the category.

## Codebook fixed before coding
2026-09-26T14:30:27Z
d03177f3b40b2061fe4ec9d38873371ce78494821859631ab5e79501a6cc7af2  p0325/codebook.md

## Adjudication rules (written after the two readings, applied to every disagreement)
R1  K needs KSDS, P1326, or knock-sensor software-update / recall / campaign wording, or an explicit statement that the
    knock sensor (system) went off and forced limp / safe / reduced power, with no physical sensor replaced. A physical
    replacement with no software or recall wording is not K.
R2  "Installed a knock sensor" under a recall means the KSDS software: sensor_replaced = no.
R3  "Fixed" or "repaired" is not "replaced".
R4  engine_failed needs seized / replaced / rebuilt / destroyed, or a shop's replacement recommendation; owner fears,
    requests, refusals and "failing" do not count.
R5  A recall mentioned as NOT applying to the vehicle is not a KSDS mention.
R6  A passing mention of a code in another story is O.
Consistency pass: after adjudication, a sweep over the agreed codes found 13 that contradict these rules; each was
read in full and corrected. Each resolved complaint carries the rule in the rule_applied column of
p0325-1554-complaints-read.csv.

## Pool history
The first search (knock sensor codes and the words "knock sensor" / "KSDS") found 1,228 complaints. An independent
audit then searched for what it missed (P1326 named without the words "knock sensor", other spellings of the
sensor); its matches were read and 322 more complaints were added, coded by the same two readers from this same
codebook, blind to each other. During fact-checking, a third sweep found 4 more complaints naming P1326 in unusual spellings; they were coded the same way, and one disagreement was resolved under R4. The found_by column says which search found each complaint.