Under the Australian Consumer Law, a major fault entitles you to choose a refund or replacement. Proving it's "major" — not just annoying — is where documentation does the work.
Build a timeline from the moment you noticed it
Note the exact date the fault first appeared, the circumstances (a specific noise, a warning light, a failure while driving), and whether it's gotten worse since. A clear timeline matters because it helps establish the fault wasn't caused by something you did after purchase.
Get an independent diagnosis
A written report from a mechanic who isn't the selling dealer carries more weight than a verbal opinion, especially if the dealer disputes the fault's cause or severity. Ask the mechanic to note whether the fault is consistent with normal wear for the car's age/mileage or points to a pre-existing issue.
Quote the repair cost
A written repair quote helps establish whether the fault meets the Australian Consumer Law's threshold for a "major failure" — broadly, one a reasonable consumer wouldn't have bought the car if they'd known about it, or that's too costly or time-consuming to fix easily.
Keep the paper trail from the sale itself
The contract, any warranty documentation, the advertised condition claims, and all communications with the dealer since the fault appeared. This is what supports your position if the dealer tries to argue the fault existed only because of how you used the car.
Sources
Related Kibbo Tools
- Car Dealer Dispute & Evidence Pack — organise the timeline, diagnosis and communications before you complain.
- Vehicle Purchase & Warranty Complaint Generator — draft your formal complaint once the evidence is in order.