Phantom braking at highway speeds—when a car suddenly slows or slams the brakes for no clear reason—can be frightening and dangerous. Many drivers report these events happening with adaptive cruise control or automatic emergency braking engaged, especially when passing big rigs, driving under overpasses, or encountering shadows and sun glare. If this keeps happening and your dealer can’t fix it under warranty, California’s lemon law may offer remedies. This post explains the basics and when to reach out to ZapLemon for help.
California Lemon Law for Phantom Braking at Highway Speeds
Phantom braking generally involves advanced driver-assistance systems (ADAS) such as adaptive cruise control (ACC) or automatic emergency braking (AEB) falsely detecting an obstacle and triggering braking. At highway speeds, that can create a serious safety risk—rear-end collisions, loss of control, or sudden swerving by drivers trying to avoid being hit. While one glitch may be inconvenient, repeated, unfixable phantom braking can add up to a substantial safety concern.
California’s lemon law—formally the Song-Beverly Consumer Warranty Act—protects consumers when a vehicle’s defect substantially impairs its use, value, or safety and the manufacturer can’t repair it within a reasonable number of attempts during the warranty period. There’s a helpful “presumption” guideline: within the first 18 months or 18,000 miles from delivery, the law may presume the manufacturer had a reasonable chance if there were (a) two or more repair attempts for a defect likely to cause death or serious injury, (b) four or more attempts for the same issue, or (c) 30 or more total days out of service for repairs. This presumption is not a hard requirement—cars outside those milestones may still qualify based on the facts.
With phantom braking, “repair attempts” can include dealer diagnostics, software updates, sensor calibrations, camera replacements, and related ADAS repairs documented on service orders. If your service invoice says “no problem found” or “operating as designed,” ask the advisor to record your description of the braking events in detail. Keep a log of dates, speeds, conditions (weather, lighting, lane markings), and whether ACC/AEB was on. If safe and legal to do so, preserve dashcam clips and submit written complaints to the manufacturer and, if appropriate, file a report with NHTSA using your VIN. Thorough documentation helps establish the pattern and the safety impact.
When to Call ZapLemon About Highway Phantom Braking
Consider contacting ZapLemon if phantom braking continues after one or more warranty repair attempts, or if the dealer says they “can’t duplicate” the issue yet the problem persists. Repeated incidents at freeway speeds, especially with passengers or cargo in the car, raise safety concerns that may substantially impair the vehicle’s use and value. It’s also a good time to call if you’ve been without your car for extended days due to ADAS-related repairs or if multiple software updates haven’t solved the problem.
Our team can review your repair history, warranty status, and communications with the dealer to help you understand your rights and options. We look at patterns: number of repair attempts, how the defect affects safety, days out of service, and whether there are technical service bulletins or recalls related to the issue. Every situation is fact-specific, and outcomes vary—this page is for general information only. A consultation helps you assess next steps, timelines, and potential remedies under California law.
Before you call, organize your materials: purchase/lease contract, warranty booklet, all repair orders and invoices, notes or videos of incidents, and any manufacturer emails or case numbers. Check your VIN for recalls on NHTSA’s website and ask the dealer to print any ADAS-related software or calibration reports. Keep using your vehicle as instructed in the owner’s manual—don’t disable safety features unless the manufacturer advises it in writing—so you can continue to document the defect. These practical steps make your consultation more productive.
Disclaimer: This article is for informational purposes only, does not constitute legal advice, and does not create an attorney-client relationship. Past results do not guarantee a similar outcome. Attorney Advertising. If you believe your vehicle may qualify as a lemon due to phantom braking at highway speeds, contact ZapLemon at (310) 489-3017 or visit https://zaplemon.com to request a consultation. We’re here to review your records, answer questions, and help you understand your options under California law.