The test can be conducted anywhere using the truck’s OBD
system provided it’s performed by a CARB-credentialed tester
using a CARB-certified readout device. When submitting
testing and reporting data using telematic devices that have
received CARB certification, a CARB-credentialed tester is
not required.
Older heavy-duty vehicles without OBD systems will use the
current opacity testing requirements with an added visual
testing component.
Testing Frequency
• OBD-equipped vehicles: 2 times per year, increasing to 4 times per year after 3 years.
• Non-OBD equipped vehicles: 2 times per year.
• Agricultural vehicles and California registered motorhomes: Once per year.