Lemon Law Attorneys Reveal: What Counts as a “Defect”

If your car keeps going back to the shop for the same problem, you’re probably wondering whether it counts as a “defect” under the California Lemon Law. At ZapLemon, we hear this question every day. The short answer: a defect is a warranty-covered problem that substantially affects the vehicle’s use, value, or safety—and that the manufacturer can’t or won’t fix after a reasonable number of repair attempts. Below, our team explains what that means in plain English and shares real-world examples to help you spot the red flags.

What Counts as a Defect Under California Law

In California, a defect (often called a “nonconformity”) is a problem covered by the manufacturer’s warranty that substantially impairs the vehicle’s use, value, or safety. It can affect new or used vehicles as long as they are still under the original manufacturer’s warranty. This includes leased vehicles and certified pre-owned cars. The issue doesn’t have to make the car undriveable; it just has to be serious enough to matter in everyday use or to a reasonable buyer.

The law also focuses on whether the manufacturer (through an authorized dealer) had a reasonable number of chances to fix the problem. There’s a helpful guideline in California: during the first 18 months or 18,000 miles, the law presumes you’ve given a reasonable number of attempts if one of these happens—4 or more repair attempts for the same problem, 2 or more attempts for a defect that could cause serious injury or death, or the vehicle is out of service for repair for a total of 30 or more days. You can still qualify outside those limits; you just won’t have the benefit of that presumption.

Not every annoyance is a defect. Issues caused by accidents, abuse, or unauthorized modifications usually aren’t covered. Normal wear-and-tear (like worn brake pads) is typically excluded, too. On the other hand, “cosmetic” problems can count if they substantially affect value—think widespread paint failure on a nearly new vehicle or chronic water leaks that cause mold. The key is whether the problem is covered by the warranty and meaningfully affects use, value, or safety.

Real-World Examples: Safety, Use, or Value Issues

Safety: Problems that make the car unsafe—even intermittently—can qualify. Examples include malfunctioning airbags or airbag lights that won’t clear, brake failures or spongy brakes that persist after service, steering that pulls or loses assist, sudden loss of power while driving, recurring fuel leaks, and advanced driver-assistance issues like phantom braking or lane-keep malfunctions. A backup camera that repeatedly fails can also be a safety defect, because it affects rear visibility.

Use: Defects that make everyday driving unreliable or inconvenient may substantially impair use. Think transmissions that slip, shudder, or refuse to shift; engines that stall at lights; EVs with charging failures or high-voltage battery faults; repeated “no start” conditions; HVAC systems that don’t heat or cool; infotainment systems that freeze, reboot, or disable controls; parasitic battery drains; and persistent check-engine lights that keep coming back for the same root cause. If you can’t rely on the vehicle to get you where you need to go, that’s a use issue.

Value: Some defects primarily hit resale value or ownership experience. Chronic water leaks, foul HVAC odors that return after treatments, peeling paint or clearcoat on newer vehicles, wind noise from poor sealing, rapid and uneven tire wear from unrepairable alignment issues, or persistent rattles on a near-new car can materially reduce the car’s value to a reasonable buyer. Even if you “can still drive it,” a recurring, warranty-covered problem that scares off buyers or diminishes the vehicle’s worth may count.

This article is for general informational purposes only and is not legal advice. Reading it does not create an attorney–client relationship with ZapLemon. Every situation is different, and outcomes depend on specific facts and applicable law. Attorney advertising.