--- title: "What Is Parts Interchange (Part Cross Reference)?" url: https://www.uncap.com/glossary/parts-interchange author: "Denis Dyli" published: 2026-10-14 updated: 2026-10-14 summary: "Parts interchange, also called part cross reference, is data that records which part numbers are equivalent: an aftermarket number that replaces an original equipment manufacturer (OEM) number, one brand's number that matches another brand's, or a discontinued number and the part that superseded it. Parts catalogs use it so any number a buyer has finds the right part." --- # What Is Parts Interchange (Part Cross Reference)? > Parts interchange, also called part cross reference, is data that records which part numbers are equivalent: an aftermarket number that replaces an original equipment manufacturer (OEM) number, one brand's number that matches another brand's, or a discontinued number and the part that superseded it. Parts catalogs use it so any number a buyer has finds the right part. **Parts interchange**: Parts interchange, also called part cross reference, is data that records which part numbers are equivalent: an aftermarket number that replaces an original equipment manufacturer (OEM) number, one brand's number that matches another brand's, or a discontinued number and the part that superseded it. Parts catalogs use it so any number a buyer has finds the right part. ## How it works This page is not a lookup tool. It covers the equivalence data behind such tools, and the seller who has to keep that data current. Uncap's own guide to cross-reference data sorts the mappings a working catalog carries into three kinds: - OEM to aftermarket. The buyer has the number off the original part and needs your equivalent. - Brand to brand. The buyer knows the part by another brand's number, and you stock the same part under a different brand. - Supersession. A manufacturer retires a number and replaces it with a new one, sometimes more than once. The catalog follows the chain to the current part. In the automotive aftermarket the data travels with the rest of the product record. The Product Information Exchange Standard (PIES), the Auto Care Association's standard for product information, lists interchanges among the information a supplier can send for its products, along with descriptions, pricing, attributes and digital assets. The association's Brand Table stores parent companies, brands and sub-brands as shared codes, which reduces errors in how brands are represented. Interchange answers a different question than fitment. Interchange says two parts are the same part. Fitment says a part fits a given vehicle. ## Example A distributor stocks one oil filter under its own SKU. Its interchange table maps five numbers to that SKU: one OEM number, three other brands' numbers and one superseded number from an older catalog. That is 1 + 3 + 1 = 5 searchable numbers for one part, and a buyer holding any of them reaches the same product page. If the superseded number is left out, a returning buyer who searches the number on last year's invoice gets no result, even though the part is in stock. ## On Shopify Shopify's online store search finds a product by its full SKU or barcode, and by the start of either. Characters from the middle or end of a code don't match unless they form a complete segment separated by hyphens, slashes or spaces. Tags are searchable keywords you can associate with a product. With the Search & Discovery app you can assign up to 10 search terms to a product, so it ranks higher when a buyer searches one of them. Shopify also notes that if a store uses a third-party search app, that app powers the online store search instead. As general practice, catalogs with many cross-references per part index them through such an app or a custom build. ## How Uncap helps Uncap's guide to [parts cross-reference data](/post/parts-cross-reference-data) puts it plainly: cross-references answer "is this the same part," fitment answers "does this fit my vehicle," and a serious parts catalog needs both, resolved against the same data layer. Uncap Garage handles the vehicle side with Year-Make-Model filtering on ACES/PIES data. ## Related terms - Fitment - OEM vs. aftermarket parts - ACES and PIES - Year-Make-Model (YMM) - SKU (stock keeping unit) - PIM (product information management) ## Sources - Auto Care Association: Product Information Exchange Standard (PIES) - Auto Care Association: Brand Table - Shopify Help Center: Search behavior in your online store ## Frequently asked questions ### What is an OEM interchange number? In plain terms, it is an aftermarket or other brand's part number that a cross reference lists as equivalent to an original equipment number. A buyer who has the OEM number off the old part can use it to find the replacement. ### Is interchange data part of the PIES standard? Yes. The Auto Care Association lists interchanges among the product information a supplier can send in a PIES XML file, alongside features and benefits, descriptions, pricing, attributes and digital assets.