California Air Resources Board

New on-road heavy-duty engines and vehicles and off-road compression-ignition engines subject, necessarily or voluntarily, to California regulations may not be sold, offered for sale, or introduced or delivered into commerce in California or imported into California unless certified by a valid Executive Order. Manufacturers are responsible for demonstrating at the time of certification that the engines and vehicles being certified employ acceptable tamper-resistance measures for all emission-related adjustable parameters to ensure that the emissions levels remain as originally certified for the duration of the applicable useful life. 

Some example of possible adjustable parameters include: 

1. Idle fuel-air mixture
2. Choke valve action parameter on carbureted
3. Turbocharger wastegate actuator

A manufacturer is solely responsible for the approval of all tamper-resistance methods for emission-related adjustable parameters.

The manufacturer is responsible for submitting samples of the adjustable parameter to CARB for tamper resistance and durability testing. The Executive Officer will use only ordinary tools when performing the tamper resistance and durability test. Ordinary tools include but are not limited to:

1. Screwdrivers (slotted, Phillips head, etc.);
2. Pliers (standard, needle nose, cutting, and locking pliers);
3. Hammers;
4. Awls;
5. Wrenches;
6. Tools supplied by the manufacturer with the product; and
7. Tools available for purchase by the general public at the time of certification (CARB will consider both storefront and internet sales)

The following regulations pertain to adjustable parameters. 

In addition, CARB has provided guidance for tamper-resistance for diesel injection pumps and other components.