Three references, three different jobs
OEM number, EPC code and interchange number are often used in the same conversation, but they do not mean the same thing. Mixing them together is one of the easiest ways to create a wrong quote.
An OEM number usually identifies a part. An EPC code usually identifies a vehicle, platform, model group or catalogue context. An interchange number usually comes from an aftermarket brand or supplier catalogue. All three can help, but none of them should be treated as the whole answer by itself.
OEM number
The OEM number is the most useful starting point when the buyer needs a specific part. It may come from the original part, EPC catalogue, old package, dealer invoice or previous purchase list.
Use the OEM number when you want to answer:
- -What is this part?
- -Which product category does it belong to?
- -Is there a replacement or branded aftermarket option?
- -Can this number be quoted directly?
An OEM number is strong, but it is not magic. Some numbers are superseded. Some are written differently by market. Some are reused in confusing ways by informal catalogues. That is why PartSail still checks the number against vehicle context and product evidence before treating it as quote-ready.
EPC code
An EPC code is usually about the vehicle or catalogue context, not the part itself. In Chinese export vehicles, this matters because the name buyers use in the market may not match the internal model code used in a parts catalogue.
Use an EPC code when you want to answer:
- -Which vehicle family does this market model map to?
- -Which catalogue should be used for fitment checking?
- -Which parts groups or diagrams are relevant?
- -Is the buyer talking about the right vehicle generation?
For example, a local market may sell a model under one public name while the EPC system uses a different internal code. PartSail's vehicle pages are built to make this relationship easier to inspect before a buyer sends a list.
Interchange number
An interchange number is a helpful supporting reference from an aftermarket catalogue. It can point to compatible products, but it can also be broader than the actual requirement.
Use an interchange number when you want to answer:
- -Which aftermarket products may replace the original part?
- -Are there known equivalents from other brands?
- -Can a distributor compare multiple supplier references?
Do not use interchange as the only source of truth for uncertain fitment. If the vehicle is new, region-specific, electric, or has multiple axle options, ask for OEM or EPC evidence as well.
How to combine them in a quote request
The best request uses the references in this order:
- -OEM number for the part.
- -Vehicle model, year, market and VIN when available.
- -EPC code or screenshot when the vehicle identity is uncertain.
- -Interchange numbers as supporting references.
- -Photos or measurements when catalogue data is thin.
If you have only one reference, send it anyway. PartSail can start from OEM Cross Reference, a product category, or a vehicle model page and then ask for the missing evidence.
Practical rule for distributors
When you are building a stock list, keep separate columns for OEM number, EPC code and interchange number. Do not merge them into one "part code" column. This small habit prevents confusion later when sales, purchasing and the supplier are looking at the same sheet.
If your team needs a structured way to clean these references, see Data Services or send a consolidated list through Bulk RFQ.