Modified Software Checks

Beginning July 19, 2021, vehicles identified with illegally modified software will fail Smog Check. Below are answers to questions on the implementation of modified software checks.

Why is the Bureau of Automotive Repair (BAR) implementing checks for modified software at this time?

Health and Safety Code section 44015 prohibits a certificate of compliance from being issued (i.e., Smog Check failure) to a vehicle that has been illegally modified (i.e., tampered). Health and Safety Code section 44036(b)(3)(K) expands upon this by preventing certificates of compliance from being issued to vehicles with irregular computer responses. Title 16, California Code of Regulations section 3340.42.2(c)(8) further clarifies by requiring that on or after January 1, 2013, On-Board Diagnostic (OBD) equipped vehicles shall fail the OBD inspection if the vehicle’s OBD system data does not match the original equipment manufacturer (OEM) or a California Air Resources Board (CARB) exempted OBD software configuration. These statutes and regulations have been in place for several years, but it has taken time to develop the data infrastructure necessary to support these provisions.

How will the illegally modified software determination be made?

The check for modified software is entirely automated once the Smog Check inspector plugs the OBD connector from the BAR OBD Inspection System (BAR-OIS) into the vehicle’s OBD port.

Yes. CARB has an Executive Order (EO) process by which aftermarket component manufacturers may submit aftermarket devices and software for certification. Once certified, these products are legal to be installed on vehicles as described by the EO for on-road use/operation in California. This process includes allowances for modifications to the engine control unit (ECU) programming. CARB provides a web tool for looking up approved modifications from their EO process. Vehicle modifications performed according to CARB EOs should not cause a vehicle to fail its Smog Check inspection.

How do consumers, whose vehicle has failed for modified software, dispute the results?

Consumers who have OEM software or CARB EO approved software installed on the vehicle but fail Smog Check due to modified software may dispute the result with the Smog Check Referee by calling 800-622-7733.

How can consumers identify illegal software modifications when purchasing a used vehicle?

BAR’s vehicle Smog Check history search tool allows consumers to search for a vehicle’s Smog Check inspection results, including any failures for modified software that occurred on or after July 19, 2021.

Inspection results are also printed on the vehicle inspection report (VIR) provided after each Smog Check. Consumers are encouraged to request a copy of the VIR and review the inspection results before purchasing a used vehicle.

Before purchasing a legally-modified vehicle, consumers can verify the approved modification using the CARB EO web tool.

Consumers who unknowingly purchase a vehicle with illegally-modified software, may file a complaint with BAR.

The aftermarket installation must have a CARB EO approval for use on that specific vehicle. To obtain EO information prior to installing a tune, contact the aftermarket part manufacturer and visit CARB’s aftermarket parts database.

What is the penalty for returning a vehicle to stock to pass the Smog Check inspection and then tuning it again? Are there any measures to ensure that doesn't happen?

An illegally tuned vehicle could be cited for a violation of California Vehicle Code section 27156(b).

Additional Information