Self-driving features promise safer and less stressful commutes, but when autonomous systems misbehave—phantom braking, erratic lane-centering, or cameras that can’t calibrate—California consumers are left wondering whether the Lemon Law can help. At ZapLemon, we explain how California’s rules apply to modern driver-assistance and “autonomous” functions so you can make informed choices about your next steps.
How California Lemon Law Applies to Self-Driving Defects
California’s Lemon Law (the Song-Beverly Consumer Warranty Act) applies to new and certain used vehicles sold or leased with a manufacturer’s warranty. If a defect covered by that warranty substantially impairs the vehicle’s use, value, or safety—and the manufacturer or its authorized dealer can’t fix it after a reasonable number of attempts—you may be entitled to remedies such as repurchase or replacement. That framework includes advanced driver-assistance and autonomous driving features when they are part of the vehicle’s warranted systems.
What counts as a “reasonable” number of repair attempts depends on the facts. California’s legal presumption (often referenced as the Tanner presumption) generally looks at repair attempts within the first 18 months or 18,000 miles: four or more attempts for the same nonconformity, two or more if the defect is likely to cause death or serious bodily injury, or the vehicle being out of service for 30 or more cumulative days for warranty repairs. These are guidelines, not hard caps—cases outside these windows can still qualify depending on the circumstances and evidence.
Self-driving defects can be tricky because they may appear intermittently and involve software, sensors, radar, lidar, or cameras. Even if a manufacturer labels a feature “driver assistance,” repeated failures that affect safe operation—like sudden braking at highway speeds, inconsistent steering inputs, or adaptive cruise control that misreads traffic—can still constitute a substantial impairment. Used vehicles with active manufacturer warranties, certified pre-owned cars, and vehicles receiving over-the-air updates may all fall under the law’s protections, depending on warranty terms and repair history.
Common self-driving failures, repairs, and records
Consumers frequently report issues such as phantom braking on clear roads, lane-centering that “ping-pongs” or disengages without warning, driver monitoring errors that falsely claim inattentiveness, or camera/radar miscalibration that persists after repairs. Other examples include self-parking that aborts mid-maneuver, low-speed collision-avoidance triggers with no obstacle present, and over-the-air updates that introduce new faults or don’t install successfully. These problems can be exacerbated by weather, road markings, or glare—but repeated or severe malfunctions may signal a defect.
Dealers commonly attempt repairs like sensor or camera replacements, software updates or rollbacks, alignment and calibration procedures, wiring harness checks, and module replacements (ADAS ECU, radar units, camera assemblies). Many manufacturers rely on data logs to analyze events; sometimes they’ll ask you to return after an update “learns” or after a calibration drive cycle. If your vehicle keeps returning for the same self-driving issue—especially if the dealer notes “no trouble found” even though the systems misbehave—you’ll want a clear, written record of each visit and what was done.
Practical steps can help you document your experience. Keep every repair order and make sure it accurately describes your complaint (e.g., “phantom brake events at 65 mph in clear conditions,” “lane-keep disengages on straight highway”). Note dates, mileage, weather, road type, and whether other features were active. Save screenshots or photos of dashboard alerts when safe to do so, and keep update notes or release versions from over-the-air installs. Ask the service department to attach error codes, calibration results, and data log summaries to the repair file. Clear records can help demonstrate both the severity of the defect and the number of repair attempts or days out of service.
This article is for 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, warranty terms, and documentation. If you believe your vehicle’s autonomous or driver-assistance systems have ongoing defects, consider a consultation to review your options. Contact ZapLemon at [phone number] or visit [website] to speak with our team about your circumstances.