What to know — Performance smog rules in California
Do modified or performance vehicles pass California smog? A modified or performance vehicle can pass California smog only if every emission-related component carries a valid CARB Executive Order (EO) number. Parts without an EO cause an automatic visual inspection failure, regardless of tailpipe results.
- CARB EO numbers are issued per part, per vehicle application — the correct EO must match the installed part to that specific vehicle's year/make/model.
- Common modified-vehicle fails: cold-air intakes without EO, catback exhausts replacing catalyst sections, ECU tunes without EO certification.
- Aftermarket catalytic converters must be CARB-compliant for the specific vehicle — aftermarket cats without EO are an automatic fail.
- Engine swaps require the donor engine to be the same year or newer than the vehicle being smogged, and all emissions equipment intact.
- BAR Referee program handles vehicles with complex modification situations that a standard STAR station cannot certify.
- OBD-II scan reveals the presence of aftermarket tunes that may have altered fuel/spark/EVAP calibrations.
Per CARB Executive Order certification database and BAR visual inspection protocol.
About Performance & Modified Vehicle Smog Check at Smog Check Garden Grove
Specialized performance & modified vehicle smog check performed at Smog Check Garden Grove, our Garden Grove location.
Visit us for performance & modified vehicle smog check
- Address: 13501 Magnolia St, Garden Grove, CA 92844
- Phone: (657) 206-2767
- Website: https://www.smogcheckgg.com/
- Hours: Mon-Fri 8 AM – 6 PM · Sat 8 AM – 4 PM
What we do
- California-required smog inspection
- OBD-II readiness verification
- Same-day electronic DMV certificate filing
- Walk-ins welcome (no appointment needed)
- Bilingual English / Spanish service
*Regenerated 2026-05-25 from GBP-verified canonical data.*