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California Smog Inspectors to Check for Illegally Tuned Vehicles

By SEMA Washington, D.C., Staff

Beginning July 19, California’s Bureau of Automotive Repair (BAR) will fail motor vehicles during their biennial “smog check” inspection if they are found to have software modifications not provided by the original equipment manufacturer (OEM) or approved through a California Air Resources Board (CARB) Executive Order (EO).

BAR, which has had the authority to implement such inspections since 2013, has been gathering information from inspected vehicle ECUs since 2015. The gathered information includes CAL-ID (equivalent to a file name), CVN (equivalent to a checksum), EO status, and Vehicle Identification Number (VIN). This accumulated data is the basis upon which failure criteria will be determined. Disputed results will be referred to state-run Referee centers for further inspection.

SEMA is working with BAR to ensure that legally modified vehicles do not inadvertently fail inspection. During a meeting of the BAR Advisory Group on July 15, BAR staff expressed confidence that non-tuning ECU modifications, such as aftermarket wheel and tire calibrations, would not result in failed inspections. A recording of the meeting will be posted to the California Department of Consumer Affair’s YouTube channel in the coming days.

BAR anticipates approximately 5-10 vehicles will fail each day for illegally modified software. For context, BAR inspects approximately 1 million vehicles each month as part of the smog-check program. Roughly 10,000 of these inspections result in failures due to problems other than modified software.

SEMA encourages its members that manufacture performance-related products, including ECU modifications, to obtain CARB EOs to ensure compliance with emissions regulations.

For questions, please contact Peter Treydte at