Infiniti Q40 Reliability

Infiniti Q40 years to avoid — and the best ones

Ranked by complaints per production run rather than by raw count. A raw count only tells you which year sold well — the best-selling year always looks like the worst car. Dividing by the number of runs removes sales volume and leaves the fault rate.

When it starts to break

Not the calendar year the complaint was filed — the age of the car when it failed. That age decides who pays: inside the warranty the manufacturer does, outside it you do.

Basic warranty on this car is 4 years / 50,000 miles. Only 28.6% of reported failures happen inside it — the remaining 71.4% come out of the owner's pocket. Powertrain cover (6 years / 70,000 miles) reaches further, but it only covers engine and transmission, and most complaints here are not either.

What actually fails — and at what age

Ordered by how often owners reported each system, with the age at which it typically goes. On a Infiniti Q40 the early trouble is Air Bags and Unknown Or Other — reported at around 3 years, so a car still under warranty is the one to check for it. What waits further out is Structure at 9 years — past every basic warranty, and the bill lands on whoever owns the car then.

What else in this class

Same vehicle class as the Infiniti Q40, so the comparison is fair — an estate against an estate, not against a coupé. These 6 share its class; open any of them to see its own build years and failure ages side by side with the Q40.

These are totals, not rates: a model that sold in millions collects more of both. Open one to see its complaints per production run — the figure this site is built on.

How we measure it

Reliability scores usually arrive as a number out of five with no working shown. The Infiniti Q40 figure here comes out of 8 individual reports, and here is exactly how they were turned into a rate — two steps in it are arguable and you should be able to argue with them.

Rate, not total. Volume alone would decide the ranking, so we divide by the number of production runs — the distinct first-eleven-character VIN prefixes on record. The Infiniti Q40 alone splits into 7 runs carrying 8 complaints — 1.14 per run against 3.73 for the market.

Age, not year. Incident date minus model year gives the age at failure, which is what the warranty question turns on. It is why our «worst year» rankings exclude anything built in the last 6 years — those cars simply have not had time to break yet.

What this is not. Filing with a federal regulator takes effort, so what you see are faults someone judged serious — not scratched paint, not running costs, not how nice the car is to live with. For the Infiniti Q40 the file runs from 2015 to 2015, so the older years carry a full life of reports and the newest carry almost none.