ILLINOIS USED-CAR DATE, MILEAGE & REPAIR RECORD
Vehicle: [year, make, model]
Seller: [business name]
Keep your identifying details and original documents privately.

DELIVERY
Date: [date]
Odometer: [miles]
Supporting record: [sales agreement, delivery receipt, odometer photo]

FIRST SYMPTOM
Date: [date]
Odometer: [miles]
Symptoms and conditions: [what you observed]
Supporting record: [photo, message, diagnosis]

NOTICE TO SELLER
Date and time: [date and time]
Method and recipient: [text, phone, letter, in person; recipient]
What you reported: [details]
Proof and response: [saved message, call note, reply]

CONTINUING PROBLEM
Date range: [dates]
Odometer readings, if known: [miles]
What remained wrong: [details]
Supporting diagnosis or correspondence: [record]

REPAIR INTAKE AND RETURN — repeat for each visit
Intake date and odometer: [date; miles]
Return date and odometer: [date; miles]
Reported problem and diagnosis: [details]
Work performed: [details]
Charge: [amount and itemized invoice]
Did the same problem return? [what happened and when]
Supporting repair order: [record]

REPAIR-RELATED TRIP — repeat for each trip
Date: [date]
Start and end odometer: [miles]
Destination, driver and purpose: [details]
Supporting receipt or work order: [record]

Keep original odometer readings. Do not assume all days or miles after a symptom are excluded from the warranty period. Record the facts without deciding your legal deadline.
Keep the Buyers Guide, agreement, warranty, disclosures, estimates, invoices and communications with this log. This record is not a claim submission or proof of coverage.
Source and explanation: https://turnyourclaim.com/illinois-used-car-lemon-law/