PULSCAR ANALYSIS — P0101 AND THE MASS AIRFLOW SENSOR 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/p0101-code ------------------------------------------------------------------------------ 0. WHAT THIS FILE ADDS, AND WHAT IT DOES NOT REPEAT ------------------------------------------------------------------------------ The Check Engine Code Index already counts the manufacturer bulletins that name P0101 (70 bulletins, 10 manufacturer groups, software in at least 32, 21 of 56 outside Stellantis) and publishes its own method. https://www.pulscar.io/blog/check-engine-code-index Those figures are cited, not recomputed. This file adds the complaint side, what the individual documents instruct, and what owners report paying. ------------------------------------------------------------------------------ 1. SOURCE FILES ------------------------------------------------------------------------------ NHTSA's published flat files, loaded into SQLite without modification: complaints (777,040 received 1 Jan 2015 - 8 Sep 2026), recalls, manufacturer communications, investigations. Primary documents downloaded from static.nhtsa.gov and read in full on 23 September 2026: Nissan NTB16-027d (10141436), NTB19-045b (10171228), California campaign (10170017), NTB21-049 (10199172), NTB20-013 (10172253), NTB18-084 (10152983); GM 16139 (10126022), N192271200 (10171241), 22-NA-224 (10226122), 21-NA-032 (10191214); Kia FUE047 (10179236). Other documents in p0101-programs-and-bulletins.csv were read as NHTSA's published summary text; the "read" column says which. Statute: 42 U.S.C. 7541(i). ------------------------------------------------------------------------------ 2. TWO COMPLAINT SETS ------------------------------------------------------------------------------ A. Complaints that name P0101: SQLite FTS5 token match 'p0101' on the narrative (the tokenizer is case-insensitive): 78. All 78 were read in full: p0101-78-complaints-read.csv. A narrative that writes the code with a trailing "00" (P010100) is a different token and is not counted. Nissan 66 (Kicks 21, Sentra 18, Altima 10, Rogue 5, Versa 5, Pathfinder 4, Juke 1, Maxima 1, Rogue Sport 1), Infiniti 1, GM 9, Mazda 1, Kia 1. Filed 2025-2026: 39 of 78 (Kicks 20). Flags computed by regular expression and checked by reading: Kicks: collision / emergency braking warning 14 of 21; slip or traction light 11; stall 8 (hand count; the regex also matched "turned off"). All 78: the word "stall" 15; NHTSA crash, fire, tow flags 0. Hand reading, column maf_replaced_outcome_hand_read: sensor replaced, code or symptom returned 22 sensor "repaired", code returned 1 dealer reprogrammed and "updated" the sensor, code returned 1 sensor replaced, condition corrected 1 (2012 Versa) All 24 returns are Nissan: Kicks 9, Sentra 7, Altima 3, Rogue 2, Versa 2, Pathfinder 1. B. Complaints that mention the sensor at all: FTS candidates for "mass air flow" OR maf OR "mass airflow" OR p0101 OR "air flow sensor" OR "airflow sensor", then kept only if the narrative matches \b(MASS AIR ?FLOW|MAF|P0101|AIR ?FLOW SENSOR)\b, case-insensitive: 552. maf-complaints-by-model.csv. Nissan 214, Chevrolet 91, Ford 41. Flags: "stall" 173; crash 6; fire 6 (one is the sensor connector itself on a 1995 Mercedes SL320 with deteriorated wiring insulation; five mention the sensor in passing). ------------------------------------------------------------------------------ 3. OWNER-REPORTED AMOUNTS (maf-owner-reported-amounts.csv) ------------------------------------------------------------------------------ Every dollar figure within 160 characters of a set-B complaint's narrative was extracted (106 candidates) and read by hand. Most belonged to other repairs (transmissions, converters, engines, loan payments). 20 published in lanes: sensor replaced, paid nine installed figures $300-$725, median $500 (plus one part-only $200 and one $1,000 bill where a wrongly installed filter was blamed) sensor replaced, quoted $435 (part + reprogram), $575, over $900 sensor cleaned $120 and $126 at a shop; $10 DIY spray owner fitted the sensor $90 part duct or wiring $450 (torn intake tube), $364.44 (broken MAF wires; the code on that car was U060F) Not invoices; complaints over-represent bad outcomes. ------------------------------------------------------------------------------ 4. DOCUMENTS (p0101-programs-and-bulletins.csv) ------------------------------------------------------------------------------ 25 manufacturer documents with NHTSA document ids: Nissan and Infiniti bulletins and campaigns, GM coverage, emission recall and bulletins, Kia, Hyundai, Honda, Ford, Toyota, Mazda and Lotus bulletins. No safety recall in NHTSA's recall file names a mass airflow sensor: the recall defect, component and consequence fields contain no match for \b(MASS AIR ?FLOW|MAF|P0101)\b. ------------------------------------------------------------------------------ 5. THE WARRANTY LAW ------------------------------------------------------------------------------ 42 U.S.C. 7541(i)(1): 8 years or 80,000 miles applies to the catalytic converter, the electronic emissions control unit and the onboard diagnostic device only; (i)(2): other emission-related parts, 2 years or 24,000 miles. ------------------------------------------------------------------------------ 6. WHAT THIS IS NOT ------------------------------------------------------------------------------ Complaint counts are not failure rates: they depend on how many cars were sold, how old they are and who writes to NHTSA. The Nissan share says where owners meet this code and complain; it does not measure how often any model's sensor fails. Prices marked in the article as estimates are carried from PulsCar repair guides and were not re-checked in this pass.