The California Air Resources Board (CARB) has notified the Environmental Protection Agency (EPA) that it has finalized its rulemaking to amend provisions of the California emissions warranty and emissions maintenance schedules to extend the emissions warranty periods for 2022 and subsequent model year on-road heavy-duty diesel engines and for 2022 and subsequent model year diesel vehicles with a gross vehicle weight rating (GVWR) exceeding 14,000 pounds powered by such engines (the 2018 HD Warranty Amendments). By letter dated October 22, 2021, CARB submitted a request that EPA determine that the 2018 HD Warranty Amendments are within the scope of the previously-granted waiver for California's emission standards and associated test procedures for 2007 and subsequent model year heavy-duty diesel vehicles and engines. Alternatively, CARB requests that EPA grant California a new waiver of preemption for the 2018 HD Warranty Amendments. This notice announces that EPA has scheduled a public hearing concerning California's request and that EPA is accepting written comment on the request.