What records to keep for aftermarket parts

What Records Should You Keep for Modified Vehicle Parts?

Quick answer: For each aftermarket part, keep the receipt, the part number, the EO number if there is one, photos of the part and its label, and the paperwork that came in the box. Those details are what you'll reach for when you research a part at CARB or answer questions at a Smog Check.

Why records help

BAR's Smog Check Manual says inspectors check the aftermarket parts label for a CARB EO number. If that label is missing or illegible, the inspector may still proceed if the part can be confirmed by comparing the part number marked on the part with CARB's EO listings or the manufacturer's catalog. A clear photo of the label and part number, taken on install day, gives you a record of what the label and part showed if the label later wears off.

Your checklist

• Receipt or invoice: seller, date, part description and part number.
• Shop invoice: if a shop installed the part, the work it describes.
• Part number: exactly as marked on the part.
• EO details: the EO number and product name from the label.
• Photos: the label, the part number marking, and the part installed.
• Paperwork: installation instructions, plus any label describing required changes. CARB requires one when an install involves re-routing hoses or belts or changing tune-up specifications.
• Your EO research: a saved copy of the EO and the date you checked it.
• Vehicle details: year, make, model, engine and VIN, plus a photo of the underhood emission control label. BAR calls that label the primary source for a vehicle's emissions control requirements and certification type.
• Smog Check reports: BAR says to keep a copy of each vehicle inspection report for your records.

Practical steps

1. Make one folder per part, digital or paper.
2. Photograph labels before they get dirty or covered.
3. Add new paperwork whenever you change, reflash or remove a part.
4. Back everything up somewhere other than your phone.
5. When you sell, BAR says to give the buyer a copy of the vehicle inspection report. Your parts records can go with it.
6. Read the EO at CARB and save what you find.

Records support your research; they don't decide anything. The Smog Check inspector decides at inspection, and CARB decides which parts receive EOs.

What Showgone can and can't do here

This is what Showgone is built for: one place for each part's receipt, photos, part number and EO number, 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.

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
• BAR: Smog Check: When you need one and what's required
• CARB: Procedures for Exemption of Add-On and Modified Part(s) for On-Road Vehicles/Engines (adopted June 29, 2021), Section VIII
• CARB: Aftermarket parts lookup

Date checked: 2026-10-20