Mercedes OEM-onderdeelnummers (A-nummers) lezen: gids

A Mercedes OEM part number, commonly called an A-number, is the letter A followed by ten digits, for example A2483502600. The A prefix marks it as a genuine Mercedes-Benz part, the leading digits point to a model or engine-series family, and the remaining digits identify the part group and the specific component. Reading it correctly is the fastest way to order the exact right part.

What does the structure of an A-number mean?

The format is consistent: one prefix letter and ten digits, often written with spaces (A 248 350 26 00) for readability. The publicly well-known parts of that structure are:

• The A prefix indicates a finished Mercedes-Benz part. You will also see a Q on some accessories and consumables.
• The first three digits correspond to a model or engine-series family. In A2483502600, the 248 relates to the current-generation compact platform family.
• The following digits encode the part group and the individual part.

Beyond that broad pattern, the internal meaning of each later digit is not something to guess at. What matters in practice is that the full ten-digit number is unique to a specific part, so you match the whole number rather than trying to decode every position.

Where do you find the part number on the car?

Mercedes parts carry their number in one of two ways. Many components have the number stamped or cast directly into the metal, which is common on castings such as differentials, brackets and housings. Others carry a printed label or sticker, typical of electronic modules, sensors and boxed assemblies.

When you are hunting for the number, clean the area first, because road grime hides stampings easily. Photograph it in good light. If a part has both a stamped number and a label, note both, since they may serve different purposes as explained next.

What is the difference between a casting number and a part number?

This is where people most often go wrong. A casting number is moulded into a component when the raw part is produced. It identifies the casting, but several different finished parts can share the same casting while differing in machining, ratio or calibration. A part number (the A-number) identifies the finished, saleable part.

For drivetrain components this distinction is critical. Two rear differentials can share a casting yet have different final-drive ratios, which makes them non-interchangeable. Always order by the A-number, and where ratio matters, confirm the ratio separately. Our guide to identifying a Mercedes rear differential by OEM number shows exactly how casting marks and the A-number sit on the same unit.

Why does one part have several A-numbers?

When Mercedes revises a part, it issues a new number and marks the old one as superseded by the new one. The updated part usually fits the same applications and often incorporates a small improvement. This is why a single physical component can be listed under two or three A-numbers over its life.

For buyers, supersession is good news: if your original number is superseded, the newer number is normally the correct replacement. When you search, checking both the old and new numbers helps you find every matching listing.

How do A-numbers cross-reference to Bosch and ZF?

Many Mercedes parts are made by suppliers who assign their own numbers. Matching the two lets you confirm you have the right part from either direction. Two examples straight from our catalogue:

• Bosch diesel injector A6540700300 = Bosch 0445118034 (Mercedes OM654).
• Rear differential A2483502600 = ZF 4460 410 554 D (ZF HAG170, 2.44 ratio).

A good listing shows both the OEM A-number and the supplier cross-reference, so you can verify against whichever number you have in hand. Every listing on our site includes the OEM number plus cross-references, an honest condition grade and defect photos, and orders carry a 14-day return.

How do you use the number to search our site?

Type the A-number, with or without spaces, into the search on any transmission or fuel-system category page. If you find an exact ratio-sensitive part such as a differential, cross-check the ratio too; our 4MATIC rear differential failure guide explains why. If you are weighing new against used injectors, see our used vs new vs remanufactured OM654 comparison.

FAQ

Is the A-number the same as the VIN?

No. The VIN identifies the whole vehicle, while the A-number identifies one part. You can use your VIN at a dealer parts counter to look up which A-number your car needs, then match that number to a listing.

My part number is superseded. Which one do I order?

Order the newest superseding number unless a listing states otherwise. It normally fits the same applications as the original and may include a minor revision.

Can I trust a supplier number like a Bosch or ZF code instead?

Yes, as a cross-check. A reputable listing shows both the A-number and the supplier number so you can confirm the match from either side before buying.