What counts as a defective vehicle in Australia?

Updated on 6 October 2026

The standard a car has to meet

Any car sold by a dealership in Australia comes with the consumer guarantees under Australian Consumer Law. They apply automatically, whether or not anything was said at the time of sale, and they sit alongside the written warranty rather than depending on it.

The guarantee that does most of the work is acceptable quality. A car is of acceptable quality if it’s safe, durable, free from defects, acceptable in appearance and finish, and fit for all the purposes cars of that kind are commonly used for. That’s measured against what a reasonable buyer would expect given the car’s price, its age, its kilometres, and anything the dealership said about it or you were able to see before buying. A small hatchback and a luxury SUV are held to different versions of the same test, and so is a car at three years old compared with one at three months.

Two other guarantees come up with cars. One is that the car matches its description, in the ad, in the showroom and in the contract. The other is fit for purpose, which covers anything specific you told the dealership you needed the car to do, such as towing a particular weight, and they said it would.

So a defective vehicle, in the sense that matters for a claim, is one that falls short of what a reasonable person would have expected for that car. That’s a wider idea than a mechanical breakdown, and a narrower one than any problem at all.

Defects that tend to matter

There’s no official list, but the same kinds of fault come up again and again in car disputes, and they’re the ones most likely to reach the bar.

• Safety faults. Brakes, steering, suspension, airbags, seatbelts, lights, and anything that makes the car unsafe to drive. These weigh heavily because safety is written into the test.
• Drivetrain and engine faults. Gearbox problems, engine failures, turbo and injector failures, overheating, and major oil or coolant leaks on a car that shouldn’t be having them yet.
• Electrical and software faults. Warning lights that keep coming back, infotainment or driver assistance systems that don’t work, batteries and charging faults in hybrids and EVs.
• Water ingress and body faults. Leaks into the cabin, rust on a car too young for it, paint or panel defects from the factory.
• Repeat faults. The same problem returning after it has supposedly been fixed, even if each individual repair looked minor.
• Faults the car was sold without. Anything described as fixed, replaced or included that wasn’t.

A defect doesn’t have to stop the car dead. A car that keeps going into limp mode, or that spends weeks at a time at the dealership, may be failing the durability and fit-for-purpose parts of the test even though it still technically drives.

Defects that usually don’t

The guarantees aren’t a promise that nothing will ever go wrong. Some problems fall outside them more often than not.

• Wear and tear in line with the car’s age and kilometres
• Consumables, such as tyres, brake pads, wiper blades, bulbs and fluids, unless they failed far sooner than they should have
• Problems the dealership told you about before you bought, or that were obvious on inspection
• Damage caused after purchase, including accident damage, misuse, modifications and skipped servicing
• Things that were never promised, such as a feature the car was never advertised as having

The line isn’t fixed. A worn part that fails at a quarter of its expected life may still be a defect. A cosmetic flaw on a brand new car may count where it wouldn’t a few years in. When a dealership says a problem is wear and tear, it’s a position, not a verdict.

How serious does it have to be?

Once a fault counts as a defect, the next question is how serious it is, because that decides who gets to choose what happens next.

A serious fault is broadly one that would have stopped a reasonable person buying the car had they known about it, that makes the car unsafe, that means it can’t do what it was sold for, or that can’t be fixed within a reasonable time. Where a fault is that serious, the choice may be the buyer’s. That could mean a refund, a replacement, or keeping the car and asking for compensation for the drop in its value.

A smaller fault is anything that doesn’t reach that bar. There the dealership may be entitled to choose, and it will usually choose a repair, done within a reasonable time and at no cost to you. If the repair isn’t done in a reasonable time, or the same fault keeps coming back, a smaller fault may come to be treated as a serious one. That’s the route most repeat-repair disputes take.

Where a fault sits is a judgement about the facts, and reasonable people can disagree. Nothing on this page is advice about how serious your fault is.

New car defects

A brand new car is held to the top of the scale. The price is highest, the age is zero, and a reasonable buyer expects it to be free of faults, so defects that might be let go on an older car can count on a new one. Paint and panel flaws, rattles and trim issues, faulty electronics, early mechanical failures and problems that appear on the drive home or in the first few weeks all come up, and the fact that the car is new weighs in the buyer’s favour.

That doesn’t mean a new car with any fault is returnable. The dealership may be entitled to repair a small fault first, and a single fixed problem rarely counts as serious on its own. But a serious fault, a safety fault, or a run of repeat visits early in a car’s life can reach that bar sooner than it would on a car a few years in. We’ve covered the return side of this in can I return a brand new car to the dealership, and the broader question of returning a car to a dealer separately.

One practical point. The pre-delivery inspection and the handover are the dealership’s chance to catch defects before you take the car. If you spot something at handover, note it on the paperwork before you sign and drive away.

Defects that appear after the warranty ends

A defect that shows up after the written warranty has run out isn’t automatically outside the consumer guarantees. The guarantees run for a reasonable period, which for a car can be longer than the warranty, depending on its price and what a reasonable buyer would expect of it. A major component failing at a point when a car of that price and age shouldn’t be failing may still count. That question has its own page, my car is out of warranty, do I still have rights?

Showing a defect

A defect you can show tends to carry more weight than one you can only describe. Job cards from every visit, the service history and anything the dealership has put in writing all help. What else is worth gathering depends on the fault, and it’s one of the things we look at in a review.

It’s also worth knowing whether a fault is a known one. The regulator’s recalls database lists safety recalls by make and model.

Before you do anything

If the fault affects safety, stop driving the car. Keep every job card and message, and don’t pay for a repair you think should be covered, or accept an offer, until you know where you stand. Been sold a faulty car? covers the first few days in a little more detail.

Where brokencar fits

We read your paperwork and tell you honestly whether the fault looks like one the consumer guarantees may cover, and whether there may be a claim worth making. If there is, we put it in writing to the dealership and the manufacturer on your behalf. It costs nothing to find out where you stand, and nothing is attached to it. See what counts as a broken car, what you may be owed and how the free review works.

Further reading. the ACCC on repair, replace or refund, including when a repair, a replacement or a refund may apply.