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.
Today’s cars run on code as much as they do on gasoline or electricity. Over-the-air updates and dealer-installed patches can fix glitches, improve range, or add features—but they can also introduce new problems. At ZapLemon, our lemon car lawyers regularly hear from California drivers whose vehicles began acting up right after a software update. Here’s what to know about identifying a defective update and how California’s Lemon Law may apply.
What Counts as a Defective Vehicle Software Update
A software update can be considered “defective” when it creates or worsens a problem that materially affects your vehicle’s use, value, or safety. This isn’t about minor annoyances like a redesigned radio menu. Think updates that cause your infotainment to freeze, driver-assistance features to misbehave, the battery range to drop significantly, or the car to stall, reboot, or throw warning lights that didn’t exist before the update.
Real-world examples we see include: an over-the-air (OTA) patch that triggers repeated lane-keep or adaptive cruise faults; a camera or sensor calibration loop after an update that disables parking assist; an EV battery management update that slashes expected range or slows charging; a transmission or powertrain control update that leads to rough shifting or limp mode; or a cluster update that wipes settings and causes random shutdowns. If the problem is new after the update—or an old issue that the update failed to fix despite multiple attempts—it may be more than a simple “glitch.”
Not every issue is the manufacturer’s fault. Aftermarket tuners, unauthorized apps, or damaged wiring can cause symptoms that look like a bad update. That said, most dealer-installed or OTA updates are logged by the vehicle and the manufacturer. If something goes wrong after an official update, ask the dealer to document the software version, note the timing, and provide a repair order. If a rollback or “reflash” is available, request it and keep all paperwork—this record often becomes critical if your concerns persist.
Your Rights Under California Lemon Law for Updates
California’s Lemon Law (the Song-Beverly Consumer Warranty Act) requires manufacturers to repair warranty-covered defects within a reasonable number of attempts. Software problems are not treated differently from hardware issues—if a defect in software substantially impairs the vehicle’s use, value, or safety, and the manufacturer can’t fix it in a reasonable number of tries, lemon law remedies may be available. The same is true if your car sits in the shop for an extended time due to software-related repairs.
Updates and reprogramming attempts typically count as repair attempts. For example, if a dealer applies multiple updates to address an ADAS warning that won’t clear, or your vehicle repeatedly returns for the same infotainment or power management fault, those attempts and the related days out of service can contribute to a lemon claim. What’s “reasonable” varies, and the facts matter: severity, frequency, safety implications, and how long the vehicle is unavailable all play a role.
Practical steps you can take include: report the problem promptly and describe that it started after a specific update; keep copies of all repair orders, software version notes, and any screenshots or videos of the issue; confirm whether there are recalls or Technical Service Bulletins (TSBs); request that the dealer escalate the case to the manufacturer’s technical line; and track total days your vehicle is out of service. If the issue persists after multiple efforts, consider a consultation to understand your options under California law. A brief call with ZapLemon can help you evaluate next steps based on your documentation.
This article is for informational purposes only and is not legal advice. Reading this blog does not create an attorney–client relationship, and results can vary based on individual facts. Attorney advertising.
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