How to File a Lemon Law Claim in Illinois: Notice, Arbitration, Lawsuit

To file a lemon law claim in Illinois, you build a complete repair record during the first 12 months or 12,000 miles, send written notice of the defect to the manufacturer by certified mail, go through the manufacturer’s arbitration program if one qualifies under federal rules, and then file suit within 18 months of the date your vehicle was delivered. The New Vehicle Buyer Protection Act (815 ILCS 380) sets each of those steps, and skipping any of them can cost you the presumption that your car is a lemon.¹

Work through the steps below in order. The deadlines are short, and because arbitration can take weeks, people who wait until month 11 to begin often run out of runway before they can get to court.

First, Confirm Your Vehicle and Defect Qualify

The Act covers new passenger cars, light trucks and vans under 8,000 pounds, and recreational vehicles other than camping or travel trailers, bought or leased in Illinois for personal, family, or household use. Leases must run at least one year. Used cars, motorcycles, and boats are not covered.¹²

The defect itself has to substantially impair the vehicle’s use, market value, or safety. A transmission that slips out of gear or an engine that stalls repeatedly clears that bar. A squeaky trim piece does not. All repair attempts must begin within the statutory warranty period of 12 months or 12,000 miles from delivery, whichever comes first.

Inside that window, the law presumes you have a lemon if one of two things happens:

The same defect has been brought in for repair four or more times and still isn’t fixed.
The vehicle has been out of service for 30 or more business days total for any combination of defects.¹

The 30-day trigger counts business days and allows unrelated defects to combine. The four-repair trigger requires the same nonconformity each time.

Step 1: Build the Repair Record

Your paper trail is the case. Before you send anything to the manufacturer, pull together:

Your purchase or lease contract, showing the price, terms, and date of delivery.
Every repair order from the dealership, each one showing the date, the complaint you reported, what the dealer did, and the drop-off and pick-up dates.
Emails, letters, texts, and call logs between you and the dealer or manufacturer about the defect.

Note the specific days the car was in the shop. The out-of-service clock runs while your vehicle is being repaired, not while a loaner is sitting in your driveway. Loaner days don’t reduce your count, but written records prevent fights later about which dates actually count.

When you report a problem, describe it the same way each visit. Consistent language on repair orders is what builds the “same defect” record you need for the four-repair trigger, and it makes it harder for the manufacturer to argue later that the issue was cosmetic or trivial.

Step 2: Send Written Notice to the Manufacturer

Before the lemon presumption applies, you have to send direct written notice of the defect to the manufacturer and give them one final chance to repair it.¹ Skipping this step destroys the presumption, so don’t treat it as a formality.

Send the letter by certified mail with return receipt requested. The receipt is your proof the manufacturer got it. In the letter, include:

Your vehicle identification number.
A clear description of the defect.
A timeline of every repair attempt with dates.
An explicit statement that you are invoking your rights under the New Vehicle Buyer Protection Act.

Address it to the manufacturer’s consumer affairs department. The mailing address is usually in the owner’s manual or warranty booklet. After the manufacturer receives notice, they get one final repair opportunity. If that fails, you’ve cleared the last prerequisite before dispute resolution.

Step 3: Go Through the Manufacturer’s Arbitration Program

If the manufacturer runs an informal dispute settlement program that complies with federal standards in 16 C.F.R. Part 703, you must use it before suing.³ If no qualifying program exists, you can go straight to court.

Find the designated program in your owner’s manual or on the manufacturer’s website and submit an application describing the defect, the repair history, and the remedy you want. A qualifying program cannot charge you a fee, must have panelists sufficiently independent of the manufacturer, must issue a written decision within 40 days of receiving the dispute, and must explain its reasoning.³

Take the hearing seriously. Even if you lose and move on to court, the arbitration decision is admissible as evidence in any later lawsuit. Submit the same documentation you’ve gathered, and be ready to explain how each repair attempt failed.

What You Can Win

If you prevail, the manufacturer must either replace the vehicle with a new one from the same model line (or a comparable one if that isn’t available) or refund the full purchase price plus collateral charges such as title, registration, and destination fees.¹ The statute specifies that collateral charges do not include taxes paid on the original purchase.

From either remedy, the manufacturer deducts a reasonable allowance for your use of the vehicle before you first reported the defect, plus mileage accrued when the car wasn’t in the shop. The statute doesn’t fix a formula, so the amount is often negotiated. The earlier you reported the problem, the smaller the deduction.

For a lease, the refund covers deposits, fees, taxes, down payments, monthly payments, and any other amounts you paid in connection with the lease, and is split between you and the lienholder based on each party’s interest.¹

Step 4: File a Lawsuit Within 18 Months of Delivery

You can sue the manufacturer if the arbitration decision is inadequate, if the manufacturer refuses to comply with it, or if no qualifying program exists.² The deadline is 18 months from the original delivery date of the vehicle. Miss it and your claim under this statute is finished regardless of how strong the evidence is.

Keep the two time limits straight. The 12-month or 12,000-mile warranty period is when the defect must first appear and repair attempts must begin. The 18-month cutoff is how long you have to get into court. Because arbitration can consume several months, start the notice and arbitration process as soon as the four-repair or 30-day trigger is met.

The Act itself does not provide for attorney fee recovery. Talk to a lawyer early, because many lemon law attorneys bring parallel claims under the federal Magnuson-Moss Warranty Act (15 U.S.C. 2310), which does allow prevailing consumers to recover fees in warranty disputes.

Mistakes That Can Sink Your Claim

The manufacturer has a statutory affirmative defense: that the defect was caused by your abuse, neglect, or unauthorized modifications.¹ Aftermarket parts, lift kits, tuning software, and skipped maintenance all give the manufacturer an opening. If you suspect you have a lemon, leave the vehicle stock and follow the maintenance schedule until the claim is resolved.

The manufacturer can also argue that the defect doesn’t substantially impair use, value, or safety. Repair orders that clearly describe a safety or function problem (stalls at highway speed, brake warnings, transmission failures) are much harder to dismiss than vague complaints about noises or feel.

If Your Car Is Used

The New Vehicle Buyer Protection Act does not cover used vehicles. Illinois has a separate used vehicle protection under 815 ILCS 505/2L that requires dealers to warrant the powertrain for 15 calendar days or 500 miles after delivery, whichever comes first, with your cost capped at $100 per repair for up to two repairs.⁴ It is a narrower remedy with its own notice rules and exclusions, and the steps above do not apply to it.

1
Justia Law. Illinois Code 815 ILCS 380 – New Vehicle Buyer Protection Act
2
Office of the Illinois Attorney General. Things You Should Know About Lemon Law
3
eCFR. 16 CFR Part 703 – Informal Dispute Settlement Procedures
4
Illinois General Assembly. Illinois Code 815 ILCS 505/2L