What is the 'six-month rule' when buying a car in the UK?

Under the Consumer Rights Act 2015 (CRA 2015), if a fault appears within the first six months of ownership, it is legally presumed to have existed at the time of sale. The dealer is responsible for proving the car was fault-free when sold. After six months, the burden of proof shifts back to the buyer to prove the defect was present at purchase.

Can I return a faulty car for a full refund?

If your car develops a fault within the first 30 days of delivery, you have a 'short-term right to reject' under the CRA 2015. You are entitled to a full refund and do not have to accept a repair or replacement. After 30 days, the dealer must be given one opportunity to repair or replace the vehicle before a refund can be requested.

What are my rights if a used car develops a mechanical problem?

The Consumer Rights Act 2015 requires all cars sold by traders to be of 'satisfactory quality,' 'fit for purpose,' and 'as described.' These standards apply to both new and used cars, though factors like the vehicle's age, mileage, and price are taken into account when determining what is considered 'satisfactory.'

Does the 'six-month rule' apply to private car sales?

No. The six-month rule and the Consumer Rights Act only apply to vehicles purchased from a 'motor trader' (a VAT-registered business or professional dealer). Private sales are governed by the principle of 'caveat emptor' (buyer beware), meaning the car only needs to be 'as described' and the seller must have the legal right to sell it.

Can a car dealer refuse to fix a fault within the first six months?

A dealer can challenge the six-month rule if they can prove the fault was caused by fair wear and tear, accidental damage, or misuse by the buyer after delivery. They may also refuse a claim if the specific fault was clearly pointed out to the buyer or noted on the sales invoice at the time of purchase.

How do I prove a car fault after six months?

If you are outside the first six months of ownership, you must prove the fault was present at the time of sale. This typically requires an independent engineer’s report, service history records from the DVLA/manufacturer, or evidence of a known manufacturing defect. Your statutory rights last for up to six years in England and Wales (five in Scotland), provided you can prove the initial fault.

The 6-Month Rule: Provenance of Car Faults Under CRA 2015

When you drive a new or used car off a dealership forecourt, the last thing you expect is a mechanical failure within weeks. However, when things do go wrong, the law provides a robust safety net for consumers. Central to this protection is a specific provision within the Consumer Rights Act 2015 (CRA 2015) commonly known as the "six-month rule."

Understanding whose responsibility it is to prove a fault exists—and when it developed—is the most common flashpoint for disputes between car buyers and motor traders. As we navigate the automotive landscape in 2026, where vehicle complexity has increased with hybrid and electric drivetrains, knowing your statutory rights is more critical than ever.

What is the 'Six-Month Rule'?

Under Section 19(14) and (15) of the Consumer Rights Act 2015, there is a statutory "reversal of the burden of proof."

In simple terms, if a fault develops in a vehicle within the first six months of ownership (starting from the date of delivery), the law presumes that the fault was present at the time the vehicle was sold. This is a powerful tool for consumers because it removes the initial hurdle of having to hire independent engineers to prove a pre-existing defect.

The Reverse Burden of Proof

0–30 Days: You have a "short-term right to reject" (Section 22). You don't have to prove anything other than the car is of unsatisfactory quality.
30 Days–6 Months: The "six-month rule" applies. The law assumes the fault was there at the point of sale. The burden is on the trader to prove the car was fault-free when sold.
After 6 Months: The burden of proof shifts back to the consumer. You must prove the fault was present at the time of purchase (which often requires a specialist engineer's report).

Consumer Rights: The Three Statutory Pillars

The CRA 2015 mandates that every vehicle sold by a trader must meet three specific standards. If a car fails any of these within the first six months, the "six-month rule" is triggered.

Satisfactory Quality (Section 9): The vehicle must be of a standard that a reasonable person would expect, taking into account the price, age, and description. A 2024 luxury SUV is held to a higher standard than a 2014 budget hatchback.
Fit for Purpose (Section 10): If you told the dealer you needed the car to tow a caravan or for specific off-road use, the vehicle must be capable of performing those tasks.
As Described (Section 11): The car must match the description provided in the advert or by the salesperson. If it was advertised as having "Full Service History" and it does not, it is a breach of contract.

The Trader’s Obligations and the Right to Repair

If a fault occurs between 30 days and six months, the consumer cannot immediately demand a full refund. Under Section 23 of the CRA 2015, the trader is entitled to one opportunity to repair or replace the vehicle.

The One-Opportunity Rule

The trader has one chance to fix the specific issue. If the repair fails, or if a new fault develops, the consumer then moves to the "final right to reject" or a price reduction.

Stage	Timeframe	Consumer Right	Burden of Proof
Short-term Rejection	0 - 30 Days	Full refund	Consumer (minimal)
Repair or Replacement	30 Days - 6 Months	One free repair/replacement	Trader must disprove fault
Final Right to Reject	After failed repair	Full or partial refund	Trader must disprove fault
Post-6 Month Claim	6 Months - 6 Years	Repair or partial refund	Consumer must prove fault

How Traders Can Challenge the 6-Month Rule

It is a common misconception that the six-month rule is an "automatic" win for the buyer. A trader can legally rebut the presumption of a pre-existing fault in two specific scenarios:

The presumption is incompatible with the nature of the goods or the fault. For example, if a tyre is punctured or a brake pad is worn out after 5,000 miles of driving, these are "consumable" items. The law recognizes that these parts fail due to "fair wear and tear" rather than an inherent defect.
Evidence of Misuse: If the trader can prove the fault was caused by the consumer (e.g., putting the wrong fuel in the tank or ignoring a dashboard warning light that led to engine seizure), the six-month rule does not apply.

The Final Right to Reject (Section 24)

If the trader has attempted a repair and it has failed, or if the repair is taking an unreasonable amount of time/causing significant inconvenience, you can exercise your "final right to reject."

When rejecting a car after the first 30 days but within the first six months:

The trader is entitled to make a deduction for use. This is a calculation of how many miles you have driven and the benefit you have derived from the car.
There is no set legal formula for this deduction, but it is typically calculated at a rate of 25p to 45p per mile.
Important: In 2026, the Financial Ombudsman Service (FOS) continues to look unfavourably on dealers who apply "excessive" deductions that prevent a consumer from buying a comparable replacement vehicle.

Special Considerations for 2026: Digital Content

As modern cars are essentially computers on wheels, the CRA 2015 Sections 33 to 47 regarding digital content are increasingly relevant. If your car’s infotainment system or autonomous driving software fails, the same "six-month rule" applies. If the digital content is faulty, you have a right to a repair or replacement. If that digital fault causes physical damage to the car (e.g., software failing and damaging the battery management system), the trader may be liable for the full cost of the vehicle repair.

Practical Steps for Consumers

If you find a fault within the first six months, follow these steps to protect your legal standing:

Stop Driving: Continuing to drive a car with a known fault can be seen as "affirming" the contract or causing further damage through negligence.
Notify the Trader in Writing: Do not rely on phone calls. Send an email or letter explicitly mentioning the Consumer Rights Act 2015 and your request for a repair under your statutory rights.
Keep Evidence: Take photos of dashboard warnings, record videos of strange noises, and keep copies of all diagnostic reports.
Use CarsLink.ai: If you are worried about the history of a vehicle you've recently bought, using tools like CarsLink.ai to verify previous sale descriptions or mileage records can provide the "as described" evidence needed for a claim.

Key Takeaways

The Burden is on the Dealer: Between 30 days and 6 months, the dealer must prove the car wasn't faulty when sold.
One Chance to Fix: You must allow the dealer one opportunity to repair the fault before you can demand a refund.
Deduction for Use: If you reject a car after 30 days, the dealer can deduct money for the miles you have driven.
Private Sales are Different: The 6-month rule does not apply to private sales. Those are governed by the Sale of Goods Act 1979, where the principle of 'Caveat Emptor' (Buyer Beware) is much stronger.
Evidence is King: Even with the law on your side, maintaining a clear paper trail is essential for a successful resolution.

Disclaimer: This article is for general information only and does not constitute legal advice. For specific legal matters or before taking court action, consult a qualified solicitor or contact Citizens Advice. Consumers involved in finance disputes (PCP/HP) may also have additional protections under Section 75 of the Consumer Credit Act 1974.