Last updated: September 30, 2026. Figures mix national industry studies with data from EZCarFix's own library of 4,130 published repair guides — each section says which. See methodology.
Headline numbers
A record high in 2025, up 33% from the year before. Source: CarMD 2026 Vehicle Health Index.
AAA puts it at 11.04¢/mile; at 15,000 miles a year that's $1,656. Source: AAA Your Driving Costs 2025.
AAA's 2025 all-in figure: depreciation, fuel, insurance, maintenance, and finance. Source: AAA Your Driving Costs 2025.
The most common and the costliest check-engine repair of 2025 — most often seen on aging or poorly maintained vehicles. Source: CarMD 2026 Vehicle Health Index.
Almost half of US repair shops price labor in this band (2025 PartsTech Report, via AAA). Source: AAA.
A record high in 2025; passenger cars average 14.5 years. Older cars need more repairs. Source: S&P Global Mobility.
Parts costs rose 23% in the same year — together they drove the record $554 average check-engine bill. Source: CarMD 2026 Vehicle Health Index.
The 10 most common check-engine repairs (2025)
Average cost including parts and labor, from CarMD's analysis of tens of millions of repair records. Source: CarMD 2026 Vehicle Health Index.
| # | Repair | Avg. cost |
|---|---|---|
| 1 | Replace catalytic converter(s) | $1,511 |
| 2 | Replace oxygen sensor(s) | $287 |
| 3 | Replace ignition coil(s) and spark plug(s) | $480 |
| 4 | Replace mass air flow sensor | $346 |
| 5 | Replace ignition coil(s) | $256 |
| 6 | Replace EVAP canister purge control valve | $172 |
| 7 | Replace fuel injector(s) | $572 |
| 8 | Replace ABS wheel speed sensor | $314 |
| 9 | Replace thermostat | $324 |
| 10 | Replace spark plug(s) | $299 |
The DIY savings gap
What the same job costs as parts-only versus at a shop, using the EZCarFix Repair Cost Estimator model: parts-price ranges from our published guides, median labor hours from those guides, and the $140/hr national-average shop rate (AAA, via the 2025 PartsTech Report).
Shop: $355–$485 (2.0 hrs labor)
Shop: $490–$820 (2.5 hrs labor)
Shop: $325–$430 (2.0 hrs labor)
What America is driving
- 12.8 years — average age of US light vehicles in 2025, a record high, up two months for the second year running. S&P Global Mobility
- 14.5 years — average age of passenger cars alone; light trucks average 11.9 years. S&P Global Mobility
- 289 million — light vehicles in operation in the US. S&P Global Mobility, via Carscoops
- Older cars break more: CarMD notes that aging vehicles with more miles need more repairs as ignition coils, spark plugs, oxygen sensors, thermostats, and mass air flow sensors wear out. CarMD 2026 Vehicle Health Index
What 4,130 repair guides reveal
The figures below come from EZCarFix's own published guide library, counted September 30, 2026 — the jobs and vehicles with the deepest DIY coverage.
- Cabin air filter — 464 guides
- Oil filter change — 436 guides
- Engine air filter — 414 guides
- Spark plugs — 413 guides
- Wiper blades — 317 guides
- Toyota — 367 guides
- Ford — 364 guides
- Chevrolet — 354 guides
- Nissan — 236 guides
- Honda — 234 guides
Most-covered models: Ford F-150 (36), Honda Accord (36), Toyota Corolla (34), Subaru Outback (31), Toyota Tacoma (31), Honda Civic (31). Browse all 4,130 guides.
Check-engine codes, by the numbers
EZCarFix maintains 27 trouble-code hubs covering the most common diagnostic codes. The most-visited code pages on this site recently: P0300 (random/multiple cylinder misfire), P0101 (mass air flow sensor), and P0171 (system too lean) — based on recent EZCarFix site traffic, not national data.
- Ignoring a failing oxygen sensor can cut fuel economy by as much as 40%, according to CarMD. CarMD 2026 Vehicle Health Index
- Unresolved misfires or faulty oxygen sensors can eventually destroy the catalytic converter — the $1,511 repair at the top of the list. CarMD
- New to warning lights? Start with our check-engine-light diagnosis guide.
Methodology
National figures come from published industry studies, each cited inline: AAA's Your Driving Costs 2025 (via CarBuzz's coverage of the AAA release), CarMD's 2026 Vehicle Health Index (via CarPro's coverage of the CarMD release), the 2025 PartsTech labor-rate analysis (via AAA's autorepair article), and S&P Global Mobility's 2025 average-age analysis (via AAPEX and Carscoops).
EZCarFix figures were counted from the site's own database on September 30, 2026: 4,130 published, non-duplicate repair guides; job and make/model counts are direct database group-bys. The DIY-vs-shop examples use the Repair Cost Estimator model: parts ranges are the 10th–90th percentile of per-guide parts totals from our published guides, labor hours are the median parsed time across guides for that job, and the shop rate is the $140/hr national average. Your car, your parts prices, and your local shop rate will differ.
What we left out: we could not find a recent, citable survey on the share of US drivers who delay repairs because of cost, so that statistic is omitted rather than sourced to an aggregator. If you cite these figures, please link this page.
Frequently asked questions
The average check-engine-light repair cost a record $554 in 2025, up 33% from 2024 (CarMD 2026 Vehicle Health Index). Separately, AAA estimates maintenance, repairs, and tires at 11.04¢ per mile — about $1,656 a year for a car driven 15,000 miles (AAA Your Driving Costs 2025).
Catalytic converter replacement: it was both the most common and the costliest check-engine repair of 2025, averaging $1,511 including parts and labor (CarMD 2026 Vehicle Health Index). It most often fails on older or poorly maintained vehicles.
On common jobs, roughly $140–$350: brake pads save up to ~$280, spark plugs ~$280, and an alternator ~$350 versus shop prices at the $140/hr national-average labor rate, based on the EZCarFix Repair Cost Estimator model.
Almost half of US auto repair shops price labor between $120 and $159 per hour, according to the 2025 PartsTech Report cited by AAA. Rates run higher at dealerships and in high-cost metro areas.
12.8 years in 2025 — a record high, per S&P Global Mobility. Passenger cars average 14.5 years. Older vehicles need more repairs, which is one reason repair bills keep climbing.