Start with the records. Repair orders, warranty documents, mileage, and days out of service are more useful than general assumptions about whether a vehicle qualifies.
Automatic Emergency Braking (AEB) is supposed to help prevent collisions, not cause them. Yet many California drivers report AEB systems that slam the brakes for no reason, fail to engage when they should, or constantly trigger dashboard warnings. If your vehicle’s AEB has been in the shop repeatedly and still isn’t fixed, you may be wondering whether California’s Lemon Law applies. This article explains, in plain language, when AEB failures can qualify as “lemons” under California law and how to document the problem so you can better understand your options.
When AEB Failures Are Lemons Under California Law
California’s Lemon Law—formally the Song-Beverly Consumer Warranty Act—generally covers new vehicles and many used vehicles that are still under the manufacturer’s warranty. The key question is whether a defect that the manufacturer can’t repair after a reasonable number of attempts substantially impairs the vehicle’s use, value, or safety. AEB defects can meet that standard because they directly affect safety, whether the system brakes suddenly without reason, fails to brake when it should, or disables itself with persistent warnings.
The law includes a “Lemon Law Presumption” for problems occurring within the first 18 months or 18,000 miles (whichever comes first). Under that presumption, a vehicle may be presumed a lemon if, for example, the manufacturer or its dealers have made two or more repair attempts for a defect that could cause death or serious bodily injury, four or more attempts for the same problem, or if the car has been out of service for 30 or more cumulative days for warranty repairs. AEB issues often involve safety risks and can fall into the “serious” category, especially when they cause unexpected hard braking in traffic or disable collision avoidance functions.
Even if your situation falls outside the presumption window, you may still have rights if the manufacturer can’t fix the problem within a reasonable number of attempts while the warranty applies. Potential remedies can include a buyback, a replacement vehicle, or a cash-and-keep settlement, depending on the facts. Keep in mind that outcomes vary and there are offsets and exceptions—for example, a mileage offset for use before the first repair attempt. Software updates, recalls, and technical service bulletins (TSBs) also play a role; repeated unsuccessful updates or recall repairs can be part of your repair history and may support a claim that the defect persists.
How to Document Automatic Emergency Braking Defects
Thorough documentation is one of the most helpful things you can do. Each time you visit the dealer, ask for a detailed repair order that clearly lists your complaint in your own words, the technician’s findings, and the work performed. If the dealer cannot replicate the issue, make sure the paperwork still reflects what you reported (for example, “customer states AEB brakes unexpectedly on freeway; dealer could not duplicate”). Do not leave the service department without a copy of every repair order and invoice, even for “no trouble found” visits.
Between visits, record what you experience. Note the date, time, speed, weather, road conditions, and what the vehicle did—such as “AEB applied hard braking in the carpool lane with no vehicle ahead” or “AEB warning illuminated; no braking when the lead car stopped.” Short video clips of the warning lights, dashboard messages, or the behavior itself can be helpful if it’s safe to capture them. A simple log on your phone or in a notebook can make patterns clear, and you can share that with the service advisor so they try to reproduce the problem under similar conditions.
Also keep related paperwork like recall notices, software update confirmations, and any manufacturer communications. Check your warranty coverage and see whether there are open recalls or TSBs through the manufacturer’s website or NHTSA’s database. Avoid clearing codes or disconnecting the battery before a service visit, as that can erase diagnostic data the technician needs. If the problem is intermittent, ask whether the dealer can review stored fault codes or escalate to a field engineer. Above all, prioritize safety—don’t try to provoke the defect—and schedule service promptly when warnings appear.
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Attorney advertising. General information is not legal advice and does not create an attorney-client relationship. No result is promised or guaranteed.