Intermittent defects can qualify. Document every occurrence and request a repair order even when the dealer writes "unable to duplicate."
Intermittent defects — problems that come and go without warning rather than occurring consistently — are among the most difficult lemon law cases to build and among the most frustrating for vehicle owners. The dealership cannot replicate the problem during the service appointment, so the repair order says “could not duplicate.” Does that mean you have no case? Not at all.
Automotive technicians can only repair what they can observe and diagnose. When a defect is intermittent — a transmission that occasionally slips but performs normally on a test drive, an engine that stalls once a week but starts fine at the dealer — the technician may genuinely be unable to identify the root cause or observe the failure. The result is a series of repair orders that say “could not duplicate” or “no fault found,” which manufacturers then use to argue the defect does not exist.
This documentation problem does not mean you have no rights. California lemon law does not require that the dealer successfully repair the defect — it requires that the defect substantially impair use, value, or safety, and that the manufacturer have had a reasonable opportunity to address it. A series of “could not duplicate” repair orders is still a series of repair attempts on the underlying defect.
The key to a successful intermittent defect claim is meticulous documentation of every occurrence. Maintain a written log — or use your phone’s notes app — and record every time the defect occurs:
Over time, this log builds a detailed picture of the defect’s pattern — when it occurs, how often, and under what conditions. This documentation is powerful evidence that the problem is real and recurring, even if the dealer cannot replicate it on demand.
When possible, capture video of the defect occurring. A smartphone video showing your car’s engine stalling, a warning light illuminating, or the transmission lurching is direct evidence the dealer cannot dismiss as “could not duplicate.” Many consumers who have struggled for months to be taken seriously have had their claims resolved quickly once they showed dealers or attorneys video evidence of the actual failure.
It is also worth asking your dealer to install a data logger or keep the car overnight under conditions where the defect is most likely to occur. Some defects only manifest after extended driving, in specific temperature ranges, or under particular load conditions. Requesting that the dealer test the vehicle under these conditions shows good faith on your part and shifts more responsibility to the manufacturer to actually investigate.
Manufacturers often know about intermittent defects through warranty claims from multiple customers and issue Technical Service Bulletins (TSBs) describing diagnostic procedures and repair steps. If a TSB exists for your specific symptom, it proves the manufacturer knows the defect is real — undermining any argument that your “could not duplicate” repair orders mean the problem does not exist. You can search for TSBs at nhtsa.gov or ask your lemon law attorney to search manufacturer databases.
There is no bright-line rule for intermittent defects outside the standard thresholds. Four repair attempts (including “could not duplicate” visits) still count toward the Tanner presumption. If the defect has substantially impaired your use, value, or safety — even intermittently — and the manufacturer has had a reasonable opportunity to address it without success, you may have a valid claim. The key is whether the defect is real, documented, and recurring.
Even two failed repair attempts for a defect that creates a serious safety risk — regardless of whether those visits resulted in “could not duplicate” responses — may be sufficient to trigger the two-attempt safety presumption if the symptom (stalling, brake failure, steering loss) could cause death or serious bodily injury.