Key Takeaways
- A federal court in California denied class certification in a vehicle defect suit because evidence of the manufacturer’s knowledge varied based on when each class member bought their car.
- A consumer fraud class can fail at class certification if evidence of the defendant’s alleged knowledge post-dates certain purported class members’ purchases, as individualized issues of knowledge, duty, and reliance predominate. While limited to these facts, this decision may prompt courts weighing class certification to scrutinize the gap between when key knowledge arose and when plaintiffs purchased the products at issue.
On September 30, 2026, the U.S. District Court for the Central District of California denied class certification to Mercedes-Benz owners who alleged the automaker concealed a piston-cracking defect in its M274-LS engine. Jamil v. Mercedes-Benz USA, LLC, No. 2:22-cv-08130-FLA (AJRx), 2026 WL 2970638 (C.D. Cal. Sept. 30, 2026). Plaintiffs Lena Jamil and Shideh Khabazian sought to certify a class of California M274-LS-equipped vehicle owners who purchased or leased their vehicles from 2015 through August 23, 2022, alleging the automaker knew of the defect but failed to disclose it before sale, in violation of California’s Consumer Legal Remedies Act (“CLRA”). Id. at *4.
The court’s analysis turned on predominance under Rule 23(b)(3). It held that common questions did not predominate because the evidence needed to prove the automaker’s knowledge, as well as each plaintiff’s reliance, varied with when each class member bought their car. See id. at *5. A CLRA fraudulent-omission claim requires actual reliance, meaning the plaintiff must show the omission drove the purchase decision, which in turn depends on when the defendant knew (or should have known) of the defect and had a duty to disclose it. Id. at *4.
This is where the class fractured. According to plaintiffs’ own engineering expert, the automaker investigated the alleged defect in 2019 and understood its root causes by April 2020. Id. Plaintiffs Jamil and Khabazian, however, leased or purchased their vehicles in April and July 2016 respectively, while other putative class members did so anytime from 2015 through August 23, 2022. Id. Members who bought at different times would need different evidence as to the automaker’s knowledge, since that knowledge depended on the state of the automaker’s investigation at the time of each purported class member’s purchase. Id. at *5. The court therefore found that evidence of knowledge and reliance was “not subject to common proof,” and “individualized issues predominate over common issues with respect to the sole remaining CLRA claim.” Id. In so holding, the court cited the Ninth Circuit’s recent decision in Lessin v. Ford Motor Co., which held that evidence post-dating certain model-year vehicles cannot serve as generalized proof of a manufacturer’s pre-sale knowledge. 2026 WL 382608, at *4 (9th Cir. Feb. 11, 2026). That variability, even assuming a common defect across the class, defeated predominance.
Notably, the court was careful to tie its ruling to the specific record, not a general bar on class treatment of auto-defect claims. Id. at *5, n. 6. Nevertheless, it confirms that a wide gap between plaintiffs’ purchase dates and when key evidence of a defendant’s alleged knowledge arose can be fatal to certification.
