California State Motor Vehicle Pollution Control Standards; Malfunction and Diagnostic System Requirements for 2010 and Subsequent Model Year Heavy-Duty Engines; Notice of Decision

The Environmental Protection Agency (EPA) is granting the California Air Resources Board's (CARB's) request for a waiver of Clean Air Act preemption for amendments made in 2013 (``2013 HD OBD Amendments'') to its Malfunction and Diagnostic System Requirements for 2010 and Subsequent Model Year Heavy-Duty Engine (HD OBD Requirements) and to its Enforcement of Malfunction and Diagnostic System Requirements for 2010 and Subsequent Model-Year Heavy-Duty Engines (``HD OBD Enforcement Regulation''), collectively referred to herein as HD OBD Regulations. EPA also confirms that certain of the 2013 HD OBD Amendments are within the scope of the previous waiver for the HD OBD Requirements and HD OBD Enforcement Regulation. This decision is issued under the authority of the Clean Air Act (``CAA'' or ``the Act'').