2003 BMW 325I: what breaks, and at what mileage
What breaks on the 2003 BMW 325I
On the 2003 BMW 325I, the failure owners report most often is airbag inflator rupture, with 32 reports on file. The earliest to appear is fuel pump failure, reported by a median of 1,600 miles. Overall it scores 71 out of 100, high risk for a 2003.
High risk for a 2003 — 112th riskiest of the 330 2003 vehicles we can rate. 261 owner reports; fleet size estimated from this year's own recall paperwork.
The failures owners actually file about
Owners have reported 39 named failure modes on the 2003 BMW 325I, and the three most-reported carry 30% of everything filed, which is an unusually even spread for one model year.
Airbag inflator rupture leads with 32 reports and about 1.7 per 1,000 vehicles.
Tail light, brake light or signal failure follows with 26 reports, usually reported between 72k to 125,000 miles. 2 of those reports mention a fire.
Other electrical problem follows with 21 reports, usually reported between 30k to 115,000 miles. 2 of those reports mention a fire.
By system, the reports fall mostly into lighting (51), electrical (41) and airbag (40).
When these failures get reported
179 of the reports on the 2003 BMW 325I came with an odometer reading, and half of those were filed before 74,000 miles.
Cumulatively, 36% by 50,000 miles, 69% by 100,000 miles and 95% by 150,000 miles of the dated reports had been filed, with 1 filed above the top of the chart.
The busiest stretch is between 0 and 10,000 miles, which alone holds 11% of the dated reports.
23% of the dated reports were filed below 36,000 miles.
In the order they tend to show up: fuel pump failure around 2k, other powertrain problem around 44k, other electrical problem around 62k and other lighting problem around 75k.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
Showing the 12 most-reported failure modes of 39. The full list is in the table below.
How reports accumulate
Every report with an odometer reading, cumulative, from 0 to 200,000 miles. A further 1 report came in above that, which is why the line stops short of the top. A curve that climbs early is a car with early problems, whatever its total.
- Line share of reports filed by that mileage
- Dashed the median reported mileage
How bad it is when it goes
Across the named modes, 4 mention a crash, 11 a fire and 4 an injury. Those are the words owners used in their own complaints, and NHTSA does not verify them, but they are the closest thing in this data to a measure of what a failure actually did.
The average severity weight across every report on this year is 4.21, where a stalled engine or a failed airbag weighs many times more than a rattling trim panel, and a figure this high means the reports are dominated by failures with safety consequences rather than annoyances. The weighting is set out in full on the methodology page.
What the top failures cost to put right, as editorial estimates for an independent US shop rather than figures from NHTSA: airbag inflator rupture at $0–$0, tail light, brake light or signal failure at $100–$900, other electrical problem at $250–$2,000 and other lighting problem at $120–$1,200. Dealer labour, a seized bolt or a part that is no longer made can push any of these past the top of its range.
16% of the reports on this year sit in the engine, transmission, drivetrain or cooling systems — the four where a repair bill is usually four figures.
Every reported failure mode
| Failure mode | System | Reports | With reading | 25th | Median | 75th | Per 1,000 | Typical repair | Severity |
|---|---|---|---|---|---|---|---|---|---|
| Airbag inflator rupture | airbag | 32 | 4 | — | 26k | — | 1.7 | $0–$0 | Critical |
| Tail light, brake light or signal failure | lighting | 26 | 22 | 72k | 113k | 125k | 1.4 | $100–$900 | Moderate |
| Other electrical problem | electrical | 21 | 16 | 30k | 62k | 116k | 1.1 | $250–$2,000 | Moderate |
| Other lighting problem | lighting | 15 | 12 | 53k | 75k | 90k | 0.8 | $120–$1,200 | Moderate |
| Other body or interior problem | body | 15 | 15 | 90k | 114k | 121k | 0.8 | $200–$2,000 | Moderate |
| Other powertrain problem | transmission | 13 | 8 | 16k | 44k | 78k | 0.7 | $400–$4,500 | High |
| Headlight failure or clouding | lighting | 10 | 7 | — | 67k | — | 0.5 | $150–$1,800 | Moderate |
| Fuel pump failure | fuel | 9 | 8 | 2k | 2k | 18k | 0.5 | $600–$2,600 | High |
| Ignition switch, key fob or immobilizer failure | electrical | 8 | 7 | — | 101k | — | 0.4 | $250–$1,500 | High |
| Other engine problem | engine | 7 | 5 | — | 71k | — | 0.4 | $300–$4,000 | High |
| Stalling while driving | engine | 6 | 6 | — | 20k | — | 0.3 | $300–$2,500 | Critical |
| Radiator or coolant leak | cooling | 6 | 6 | — | 90k | — | 0.3 | $350–$1,900 | High |
| Alternator or charging system failure | electrical | 6 | 6 | — | 38k | — | 0.3 | $450–$1,600 | High |
| Wiring harness or short circuit | electrical | 5 | 5 | — | 61k | — | 0.3 | $400–$3,500 | High |
| Other suspension problem | suspension | 5 | 4 | — | 84k | — | 0.3 | $350–$2,000 | Moderate |
| Other wheel or tire problem | wheels | 5 | 1 | — | 2k | — | 0.3 | $200–$1,500 | High |
| Other visibility problem | glass | 5 | 5 | — | 75k | — | 0.3 | $150–$1,400 | Moderate |
| Seat belt or retractor failure | airbag | 4 | 4 | — | 15k | — | 0.2 | $200–$900 | High |
| Misfire or rough idle | engine | 3 | 3 | — | 8k | — | 0.2 | $250–$1,600 | Moderate |
| ABS module or sensor failure | brakes | 3 | 3 | — | 103k | — | 0.2 | $500–$2,400 | High |
| Airbag warning light or occupant sensor fault | airbag | 3 | 3 | — | 92k | — | 0.2 | $300–$1,600 | High |
| Power steering pump or fluid leak | steering | 3 | 2 | — | 63k | — | 0.2 | $350–$1,600 | Moderate |
| Other speed control problem | adas | 3 | 2 | — | 52k | — | 0.2 | $250–$2,000 | Critical |
| Transmission will not engage a gear | transmission | 2 | 2 | — | 75 | — | 0.1 | $1,500–$6,000 | Critical |
| Fuel tank, filler or EVAP failure | fuel | 2 | 2 | — | 145k | — | 0.1 | $250–$1,800 | Moderate |
| Parking brake failure | brakes | 2 | 0 | — | — | — | 0.1 | $250–$1,300 | Moderate |
| Rust or structural corrosion | body | 2 | 0 | — | — | — | 0.1 | $500–$6,000 | High |
| Other brake problem | brakes | 2 | 2 | — | 48k | — | 0.1 | $300–$1,800 | High |
| Electrical fire or melted wiring | electrical | 1 | 1 | — | 53k | — | 0.1 | $1,500–$9,000 | Critical |
| Excessive oil consumption | engine | 1 | 1 | — | 85k | — | 0.1 | $900–$6,500 | High |
| No-start or intermittent start failure | engine | 1 | 1 | — | 192k | — | 0.1 | $200–$1,800 | Moderate |
| Complete transmission failure | transmission | 1 | 1 | — | 70k | — | 0.1 | $2,800–$8,000 | Critical |
| Differential or transfer case failure | drivetrain | 1 | 1 | — | 146k | — | 0.1 | $900–$4,200 | High |
| Airbag failed to deploy in a crash | airbag | 1 | 0 | — | — | — | 0.1 | $1,000–$5,000 | Critical |
| Steering rack, gear or tie rod failure | steering | 1 | 1 | — | 95k | — | 0.1 | $700–$2,600 | High |
| Wiper or washer failure | glass | 1 | 1 | — | 8k | — | 0.1 | $120–$800 | Moderate |
| Other fuel system problem | fuel | 1 | 0 | — | — | — | 0.1 | $300–$2,200 | High |
| Other steering problem | steering | 1 | 1 | — | 2k | — | 0.1 | $350–$2,400 | High |
| Other driver assistance problem | adas | 1 | 1 | — | 150k | — | 0.1 | $250–$1,800 | High |
| Unclassified problem | other | 27 | 10 | 69k | 98k | 117k | 1.4 | — | Moderate |
Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound. Repair costs are typical independent-shop ranges for the failure, not figures from these reports.
How often, against how many were built
Scaled by an estimate of how many of these cars exist, the 2003 BMW 325I draws about 14 per 1,000 vehicles, which puts it in the 90th percentile of complaint rates among 2003 vehicles we can rate.
That denominator is the weakest number on the page and it is fair to say so plainly. Rate per 1,000 uses a fleet-size estimate derived from recall paperwork for this exact model year. It is a lower bound.
The working figure is 19,133 vehicles. If the true number is twice that, every rate on this page is half what it says; the ranking against other 2003 vehicles, which is what the risk score uses, is far more robust than the rate itself.
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The odometer reading is the one the owner gave.
Airbag inflator rupture
Tl* the contact owns a 2003 bmw 325i. While attempting to accelerate, the vehicle struck the curb and caused the passenger side air bags to deploy. There were no warning indicators illuminated. The vehicle was taken to the dealer (momentum bmw, 10002 southwest freeway, houston, tx, 855-645-6452). The air bag was previously repaired per an unknown recall; therefore, the dealer would not repair it again for free. The air bag was not replaced. The manufacturer was not made aware of the failure. The contact also received a takata settlement notice and was referred to 833-619-7579. The failure mileage was approximately 78,000.
Takata recall.... I am driving in an unsafe vehicle due to drivers airbag recall and no parts are available to fix the problem. This is not a good feeling. I worry each time I get in my car and drive. The local dealership said no parts and no loaner vehicles. So I drive and worry. Someone pulled out in front of me on 4-22-16 and I barely missed their car and thought how awful this could have turned out, if I had hit them, t-boning them, my airbag would have opened and injured me and/or killed me. I get home and called the dealership because I never heard from them since last july's first recall when they told me I would get a notification when parts where available. Still no parts, I don't want to drive my car. I am a victim of "worry".the dealership service rep. Was not very concerned nor helpful. She must be not driving a car with a "driver's side airbag that is defective" and unsafe.
Tail light, brake light or signal failure
The tail light assembly keeps failing. And I loose the tail lights. The first time this happened was in 2005 on the right hand side and now it happened on the left hand side. *tr
My dashboard panel showed a warning light indicating that the tail light was having an issue. I was told by a service center that the tail light assembly may get hot enough to melt the plastic in the housing and it will have to be replaced. Upon inspection I found that the wire harness had melted and the power supply wire for one of the lights had melted the plastic and the wire had come free. Once free, it arced to the connector pin on the bulb holder assembly and degraded that pin until the connection was lost. All plastic pieces in contact with the parts are melted and burned. I contacted the bmw service center and was told that this is not a recall issue and I was responsible for replacing these parts. Pictures are available of the parts. *tr
Other electrical problem
The computer first failed on my 2003 bmw 325i on june 15, 2003, (three weeks after I picked it up from the dealership, bmw of manhattan), causing me to lose acceleration without warning. I was travelling at 60-65 miles per hour in the far left lane of the garden state parkway. I was barely able to manuever the car to the shoulder of the road and I was lucky that there happened to be a very small shoulder on the left side of the road, as I would have never been able to make it to the shoulder on the right hand side of the road and traffic was very heavy. This sudden loss of acceleration could have easily caused a fatal accident; particularly, because the cars behind me had no way to detect that my car was only coasting. The nj state troopers had to shut down northbound traffic in all 4 lanes of the garden state parkway in order to remove my car from the parkway. The car was towed to the dealership.the dealership was unable to successfully reprogram the computer, so they sent it to montvale, nj to be reprogrammed. The dealership returned the car to me on june 20, 2003. On june 25, 2003, the computer failed again, causing the car to…
I have a bmw 325i which I purchased brand new in nov. '02. In march '03, while driving on the njtpk at 60-65mph in the left lane, the car suddenly lost its acceleration. The clocks also went off and then reset itself to 12:00. Being that I was driving in the left lane of the nj turnpike, I consider myself very lucky that I was able to cross four lanes of traffic and come to the right shoulder (there was no left shoulder). I waited for a while, restarted the car, reset the clock and hit the road again. Shortly after that the electrical system in the car starting acting up... At one occasion, I was not able to unlock the car using the remote. At another, the windows would not roll up upon pulling on the knob. The light below the rear view mirror would not come on. Most of these problems would go away after I would shut down the car and restart it. I took the car into princeton bmw where I had purchased it. They had never heard of this issue before. They kept the car for a full day and did extensive testing on it. At the end of the day they were not able to find anything wrong with the car. For the next few months I did not have any…
Recalls on the 2003 model year
NHTSA has issued 8 recall campaigns covering the 2003 BMW 325I, affecting an estimated 54,075 vehicles. A recall is a different kind of evidence from a complaint: it is the regulator and the manufacturer agreeing that something has to be fixed, and the fix is free for as long as the car exists.
The campaigns cover air bags:frontal:passenger side:inflator module, air bags and air bags:frontal:driver side:inflator module. Whether the work was actually done on the car in front of you is a question only the VIN can answer, and the manufacturer or NHTSA will answer it free.
Recalls also distort complaint counts. Publicity about a campaign reminds owners that complaining is possible, so reports for a recalled component often spike after the recall rather than before it.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE
292,948 vehicles 2020-01-15- Defect
- BMW of North America, LLC (BMW) is recalling certain 2000-2005 323iT, 325iT, 325xiT, 320i, 323i, 325i, 325xi, 328i, 330i and 330xi and 2000-2006 323Ci, 325Ci, 328Ci, 330Ci, M3 Coupe, 323Cic, 325Cic, 330Cic, and M3 Convertible vehicles equipped with non-desiccated frontal Takata PSAN inflators and PSPI passenger frontal air bag inflators containing phase stabilized ammonium nitrate (PSAN) propellant that were used as interim remedy parts for previous Takata recalls. These inflators may explode due to propellant degradation occurring after long-term exposure to high…
- Consequence
- An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
- Remedy
- BMW will notify owners, and dealers will replace the passenger's front air bag, free of charge. The recall began February 13, 2020. Owners may contact BMW customer service at 1-800-525-7417.
AIR BAGS
574,007 vehicles 2018-06-11- Defect
- BMW of North America, LLC (BMW) is recalling certain model year 2000 323i sedans, coupes, convertibles, and Sports Wagons; 2000 328i sedans and coupes; 2001-2005 325i sedans, coupes, convertibles, and Sport Wagons; 2001-2005 325xi sedans and Sports Wagons; 2006 325i coupes and convertibles; 2001-2006 330i sedans, coupes, and convertibles; 2001-2005 330xi sedans; and 2001-2006 M3 coupes and convertibles to address a safety defect in the passenger side frontal air bag which may produce excessive internal pressure that could cause the air bag inflator to rupture upon…
- Consequence
- In the event of a crash necessitating deployment of the passenger's frontal air bag, excessive internal pressure could cause rupturing of the inflator resulting in metal fragments striking and potentially seriously injuring the passenger seat occupant or other occupants.
- Remedy
- Owners are advised not to drive their vehicles until they have been repaired. BMW will notify owners, and dealers will replace the passenger side frontal air bag, free of charge. An interim notice was mailed to owners in September 2014. A second notice was mailed when an adequate supply of parts became available, on December 1, 2014. Owners may contact BMW customer service at 1-800-525-7417 or email BMW at CustomerRelations@bmwusa.com.
AIR BAGS:FRONTAL:DRIVER SIDE:INFLATOR MODULE
419,235 vehicles 2015-05-28- Defect
- BMW of North America, LLC (BMW) is recalling certain model year 2002-2005 325i, 325xi, 330i, and 330xi Sedans, and 325xi and 325i Sportswagons, 2002-2006 330Ci, 325Ci, and M3 Convertibles and 325i, 330i, and M3 Coupes, 2002-2003 M5, 540i, 525i Sedan, and 530i Sedans, and 540i and 525i Sportswagons, and 2003 X5 3.0i and 4.4i Sports Activity Vehicles. Please note that the 5-series and X5 vehicles are only included if they are equipped with the optional sports steering wheel. The affected vehicles are equipped with a dual-stage driver frontal air bag that may be susceptible…
- Consequence
- In the event of a crash necessitating deployment of the driver's frontal air bag, the inflator could rupture with metal fragments striking the driver or other occupants resulting in serious injury or death.
- Remedy
- Owners are advised not to drive their vehicles until the vehicle has been remedied. BMW will notify owners, and dealers will replace the front driver air bag module, free of charge. The recall began Aug 2016. Owners may contact BMW customer service at 1-800-525-7417. Note: This recall supersedes recall 14V-348 in its entirety. Additionally, vehicles that have had their driver side frontal air bag replaced previously as part of a recall remedy need to have their air bag replaced under this recall as well. Note: On December 17, 2015 BMW removed the model year 2004 X5 3.0i…
AIR BAGS
43,204 vehicles 2013-05-02- Defect
- BMW is recalling certain model year 2002-2003 325i, 325xi, 330i, 330xi sedans; 325Ci and 330Ci coupes and convertibles; 325iT and 325xiT Sports Wagons; and M3 coupes and convertibles to address a safety defect in the passenger side frontal air bag which may produce excessive internal pressure causing the inflator to rupture upon deployment of the air bag.
- Consequence
- In the event of a crash necessitating deployment of the passenger's frontal air bag, the inflator could rupture with metal fragments striking and potentially seriously injuring the passenger seat occupant or other occupants.
- Remedy
- Owners are advised not to drive their vehicles until they have been repaired. BMW intends to issue initial notifications to owners informing them of the safety defect in June 2013. Once replacement parts are available, estimated for July, BMW will notify owners again to contact their dealers and schedule a replacement of the passenger air bag, free of charge. Owners may contact BMW customer service at 1-800-525-7417 or email BMW at CustomerRelations@bmwusa.com.
EXTERIOR LIGHTING:TAIL LIGHTS
241,000 vehicles 2011-08-26- Defect
- Bmw is recalling certain model year 2002-2005 325i, 325xi, 330i, and 330xi vehicles manufactured from september 1, 2001, through march 1, 2005. Over time, resistance in the electrical contacts may cause one or more rear lamp functions (tail light, brake light, and/or turn-signal), within the vehicle's body panel, to stop working.
- Consequence
- Intermittent light operation reduces the ability to warn other motorists of the driver's intentions. This could cause a vehicle crash without warning.
- Remedy
- Bmw will notify owners, and dealers will repair the vehicles free of charge. The safety recall began on february 15, 2012. Owners may contact bmw customer relations and services at 1-800-525-7417.
SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:MASTER CYLINDER
13,128 vehicles 2007-03-29- Defect
- Certain cardone master cylinders with part numbers 10-2925, 10-2987, 10-2987mza, 10-3083, 11-3015, 11-3042, 11-3044, 11-3045, 11-3047, 11-3064, and 11-3156, and with date codes lower than dca7078 sold as replacement equipment for use on the vehicles listed above. The seal on master cylinder can fail and leak brake fluid.
- Consequence
- Loss of brake fluid can result in poor braking performance, possibly resulting in a vehicle crash.
- Remedy
- Cardone will notify owners and offer to repurchase any defective master cylinders. The recall began during april 2007. Owners can contact cardone at 1-800-777-4780.
VISIBILITY:POWER WINDOW DEVICES AND CONTROLS
13,100 vehicles 2003-04-29- Defect
- On certain passenger vehicles, the window lifting anti-pinching device might not function properly.
- Consequence
- Occupants could be pinched by a window that is being closed.
- Remedy
- Dealers will inspect, and if necessary, replace the electronic control unit for the window lifting anti-pinching device. Owner notification began may 27, 2003. Owners who take their vehicles to an authorized dealer on an agreed upon service date and do not receive the free remedy within a reasonable time should contact bmw at 1-800-831-1117.
VEHICLE SPEED CONTROL
1,056 vehicles 2003-03-31- Defect
- On certain passenger and sport wagon vehicles with automatic transmissions, with the engine running, and the vehicle at rest, an increase of engine idle speed (up to 1,300 RPM) may occur.
- Consequence
- If a gear is selected, the driver may feel as if the vehicle is being pushed.
- Remedy
- Dealers will reprogram the digital engine management control unit. Owner notification began may 5, 2003. Owners who take their vehicles to an authorized dealer on an agreed upon service date and do not receive the free remedy within a reasonable time should contact bmw at 1-800-831-1117.
Recall work is free at a franchised dealer regardless of the car's age. Check the VIN at nhtsa.gov/recalls before assuming it was done.
How it ranks in the 2003 field
The score at the top of the page, placed among its peers. The zones are the same thresholds the scorer applies, read out of the scorer itself, so the picture and the band word cannot disagree.
Scores are ranked within the model year, never across years, because an older car has had longer to accumulate reports.
- Left fewer and less serious reports
- Right more, or worse
- Marker this vehicle
Better and worse years of the same car
High risk for a 2003 — 112th riskiest of the 330 2003 vehicles we can rate. Every score on this site is a rank inside its own model year, which is what makes a 2004 and a 2019 comparable at all.
Across the 6 model years of this car that carry enough reports to score, 2005 comes out best at 66 and 2003 worst at 71, with 2003 itself at 71.
If the model year is negotiable, 2005, 2004 and 2002 score lower than 2003 by a margin worth acting on. Same body, same engines, different luck — usually a supplier change or a mid-cycle fix, which the complaint data can show but never explain.
Within the 1999–2006 generation specifically, 2005 is the strongest year at 66 and 2003 the weakest at 71.
Scores compare each year against other cars of the same model year, so a low number on an older car is a real result and not an artefact of age.
Shorter is better. Years with too few reports to score are shown without a bar rather than as a zero, because no data is not good news.
Within the 1999-2006 generation, 2005 BMW 325I scores best at 66 and 2003 BMW 325I worst at 71.
What the numbers say to check
The mileages below are where the first quarter of reports for each mode had already been filed, which makes them the point at which a fault is worth looking for rather than the point at which it happens: fuel pump failure from about 2k, other powertrain problem from about 16k, other electrical problem from about 30k and other lighting problem from about 53k.
On a 2003 BMW 325I with more miles than that on it, the useful question to put to a seller or a mechanic is whether fuel pump failure has been dealt with, and if so with what parts and at whose expense. A car that has already had the repair is in a different position from one that has not.
None of this is a diagnosis. It is a list of what other owners of the same model year reported, ordered by when they reported it, which is a good place to point an inspection and a poor place to stop.
What this page cannot tell you
261 owner reports; fleet size estimated from this year's own recall paperwork. Every count on this page is therefore a floor: it is the number of owners who went to the trouble of filing with a federal agency, which is a small and self-selected fraction of the owners who had the fault.
Of those 261 reports, 179 carried an odometer reading, so the mileages here describe 69% of the sample rather than all of it. Owners also round: readings pile up on multiples of ten thousand, which is why this site publishes "about 90,000 miles" and not "91,438".
Named failure modes come from matching phrases in the complaint text, so a badly worded complaint can land in the wrong bucket. The effect washes out across hundreds of reports and does not wash out across five.
And nothing here predicts what one car will do. These are other people's complaints, filed years apart, on cars maintained by strangers. Read the page as a map of where this model year has previously gone wrong, then have the specific car in front of you inspected.
Questions this page answers
What are the most common problems with the 2003 BMW 325I?
The most-reported failures are airbag inflator rupture (32 reports, median 25,000 miles), tail light, brake light or signal failure (26 reports, median 115,000 miles) and other electrical problem (21 reports, median 60,000 miles). Counts come from owner complaints filed with NHTSA, which are voluntary, so they show what owners bothered to report rather than every fault that occurred.
At what mileage do 2003 BMW 325I problems start?
Fuel pump failure is the earliest failure mode to show up, with a median reported mileage of 1,600 miles and a quarter of reports before 1,600 miles. Across all failure modes on this year, the median report sits at 74,000 miles.
Is the 2003 BMW 325I reliable?
It scores 71 out of 100 on our risk index, which is high — 112th riskiest of the 330 2003 vehicles we can rate. The score is a comparison against other 2003 vehicles, not a prediction about any individual car, and it is built from complaint rates, severity and how early failures appear.
Which year of the BMW 325I is best?
Within the 1999–2006 generation, 2005 scores best at 66 out of 100 and 2003 worst at 71. Same body, same engines, different luck.
Where this comes from. Every figure above is computed from NHTSA owner complaints and recall records for this exact make, model and year. Complaints are voluntary and self-selected, so treat counts as a floor. The methodology page writes out each formula, and the same numbers are available as JSON.
What breaks at my mileage Compare with another car
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed