How to check whether an EO lists your vehicle

How to Check Whether an EO Lists Your Vehicle

Quick answer: Open the EO at CARB, find the list of covered vehicles, and compare it detail by detail with your vehicle and your part number. If anything is unclear, ask CARB, and remember the Smog Check inspector makes the call at inspection.

Step 1: Gather your vehicle details

BAR's Smog Check Manual gives examples of the vehicle configuration details inspectors match for aftermarket catalytic converters: year, make, model, engine, GVWR and fuel type. That configuration check applies to OBD II vehicles only. Collect those details for your vehicle.

Also photograph your underhood emission control label. BAR calls it the primary source for a vehicle's emissions control requirements and its certification type (California or Federal).

CARB groups vehicles into engine families or test groups for certification, and CARB's exemption procedures ask manufacturers to list covered vehicles along with their test groups, engine families and evaporative families.

Every vehicle sold in the United States has a unique drive-train identifier called the "Test Group" or "Engine Family" number. Look for it on the Vehicle Emission Control Information (VECI) label in the engine compartment, usually on the underside of the hood. CARB's diagram also shows the engine valve cover and radiator shroud as label locations. The label lists the evaporative family on a separate line, so keep the two apart.

Step 2: Open the EO

Read the EO at CARB. Choose the part type, then find the EO record. BAR says CARB's EO parts listings include the vehicles a part can be installed on.

Step 3: Compare line by line

• Model year (or range)
• Make and model
• Engine
• Test group or engine family, if listed
• Any other details the EO lists, such as GVWR or fuel type

Step 4: Match the part number

Confirm the part number on your part appears in the EO. Kits and individual pieces can carry different numbers.

Step 5: Read the conditions

EO listings may describe modifications that are necessary and acceptable for installing a part. CARB also requires a label describing required changes when an install involves re-routing hoses or belts or changing tune-up specifications.

Step 6: Look for updates

CARB has an application category for manufacturers adding model years for carryover vehicles, so an EO's coverage can change. Check the current record, and note the date you looked.

When it's not clear

Ask the CARB helpline at (800) 242-4450 or helpline@arb.ca.gov. For inspection questions or disputes, contact the Smog Check Referee at (800) 622-7733. CARB decides what an EO covers, and the inspector decides at your Smog Check.

What Showgone can and can't do here

Showgone keeps your vehicle details, part numbers and saved EO copies together, with a link to check the EO at CARB. Showgone isn't CARB, BAR, the DMV or a smog station, and a Showgone record isn't an official certificate or a coverage decision.

Add this part to your free Showgone garage.

Not legal advice.

Sources

• BAR: Smog Check Manual (April 2025), Sections 1.3.1 and 1.3.2, Appendix C (Catalytic Converters)
• CARB: California Racing Vehicles: Aftermarket Parts & Executive Orders
• CARB: Procedures for Exemption of Add-On and Modified Part(s) for On-Road Vehicles/Engines (adopted June 29, 2021), Sections III(b)(2) and VIII
• CARB: Locating vehicle "Test Group" or "Engine Family" Number
• CARB: Manufacturers of Aftermarket Parts (Category I forms)
• CARB: Aftermarket parts lookup
• CARB: Aftermarket, Performance, and Add-on Parts (contact information)
• BAR: On-Board Diagnostic Test Reference (Referee contact)

Date checked: 2026-10-20