What Are ETK, ETKA, PET, and EPC Original Parts Catalogs?
ETK, ETKA, PET, and EPC are manufacturer-specific electronic parts catalog systems used to look up genuine OEM part numbers, exploded diagrams, and assembly information for a given vehicle. Each abbreviation belongs to a different automaker group: ETK for BMW, Mini, and Rolls-Royce; ETKA for Audi, Seat, Skoda, and Volkswagen; PET for Porsche; and EPC for Mercedes-Benz, Smart, and several GM and Saab brands. They are identification and reference tools — you use them to find the correct part number before ordering, not to buy parts directly.
What each system covers
| System | Full context | Brands covered |
|---|---|---|
| ETK | Electronic parts catalog for the BMW Group | BMW, Mini, Rolls-Royce |
| ETKA | Electronic parts catalog for the Volkswagen Group | Audi, Seat, Skoda, Volkswagen |
| PET | Porsche parts catalog | Porsche |
| EPC | Electronic parts catalog (used across several makers) | Mercedes-Benz, Smart, Buick, Cadillac, Chevrolet, GMC, Hummer, Oldsmobile, Pontiac, Saab, Saturn |
The naming is not standardized across the industry — "EPC" is a generic label that multiple manufacturers have applied to their own systems, which is why the same three letters can point to different catalogs depending on context.
What these catalogs actually contain
A parts catalog entry typically gives you:
- The OEM part number — the manufacturer's own identifier, distinct from aftermarket or cross-reference numbers.
- Exploded diagrams — visual breakdowns of assemblies (engine, suspension, trim, electrical) with each component numbered.
- Assembly relationships — which parts belong to which group, and how they fit together.
- Vehicle applicability — the models, years, or variants a part is listed for.
The practical value is accuracy. A diagram plus a part number lets you confirm you are ordering the exact component that belongs in your vehicle, rather than a visually similar part that may not fit.
How people use them
The typical workflow is: identify your vehicle (model, year, variant), navigate to the relevant assembly group, locate the component in the diagram, and read off the part number. That number is then used to order from a dealer, a parts retailer, or a cross-reference service.
This matters most when:
- A part has been superseded or revised, and you need the current number.
- You are repairing rather than replacing a whole assembly.
- You want to verify a seller's listing against the factory number.
Where WebAutoCats.com fits
WebAutoCats.com is a web resource that aggregates access to these genuine parts catalogs — ETK, ETKA, PET, and EPC — across the brands listed above. It functions as a discovery and reference entry point for the catalogs rather than as a storefront. If you need to look up an OEM part number for one of the covered brands, it is the kind of resource that points you to the relevant catalog system.
Common points of confusion
- ETK vs. ETKA — similar-looking names, different manufacturer groups. ETK is BMW Group; ETKA is Volkswagen Group.
- EPC is not one system — it is a label reused by several makers, so always confirm which manufacturer's EPC you are in.
- Catalog ≠ inventory — a catalog tells you what part number exists and where it belongs. It does not confirm current availability or price; that comes from the seller.
- Region and variant matter — the same model sold in different markets can use different parts, so match the catalog to your vehicle's actual specification.