- HSN and TSN
- The Herstellerschlüsselnummer (HSN) is a four-digit code naming the vehicle manufacturer. The Typschlüsselnummer (TSN) is a three-character alphanumeric code naming type, variant and version. Both are issued by the German Federal Motor Transport Authority.
Where the numbers appear
In today's registration certificate part I they sit in fields 2.1 (HSN) and 2.2 (TSN). In the older German registration documents issued before October 2005 they were at positions 2 and 3. The same numbers, a different place on the paper.
The parts trade usually treats them as one „key number“ and enters them in a single field, for example 0600/ABC. Order matters: four digits for the manufacturer, three characters for the type.
| Element | Length | Field in part I | Describes |
|---|---|---|---|
| HSN | 4 digits | 2.1 | The vehicle manufacturer, for example 0600 for Volkswagen |
| TSN | 3 characters | 2.2 | Type, variant and version within that manufacturer |
What the key number does
In Germany the combination of HSN and TSN is the established entry point into almost every parts catalogue, tyre calculator and insurance classification. It is short, it is printed on the registration document and it can be read out over the phone. As a first access route it is hard to beat.
It describes a type, however, not an individual vehicle identity. All vehicles under the same type approval share the same key number — across build years, trim lines and engine variants, as long as those fall under the same version.
Where the key number runs out
- Equipment-dependent parts. Air conditioning, seat heating, driver assistance, tow bar — whether they are fitted is not in the type key.
- Changes during the build period. A facelift or a change of supplier alters part numbers without necessarily changing the key number.
- Imported vehicles. A vehicle never registered in Germany has no German key number.
- Conversions and individual approvals. After an individual approval the fields may be filled differently.
- Old vehicles. For classics and very old model lines the data sets are patchy.
The practical route in a dismantling yard
At intake the key number is often the first hard fact available, because the registration document is at hand. It is good for a quick classification — make, model, engine. For the vehicle file and everything later attached to a part, the VIN should nonetheless be the leading identifier.
- Take the key number from the document to classify the vehicle roughly.
- Capture the VIN and set it as the leading identifier of the vehicle file.
- Resolve vehicle data via the VIN; the key number stays in the record as an additional search attribute.
- Attach removed parts to the VIN, not to the key number — see Part identification: from removed component to sellable record.
- Publish both in listings: buyers search with whatever they have in hand.
The key number in listings
For listings in the German market it pays to carry HSN and TSN — many buyers search that way because the registration document is in front of them. As the only fitment statement it is not enough: equipment-dependent parts need the OE number, and electronic components additionally need a note about required coding.
Frequently asked
Where do I find HSN and TSN?
In the German registration certificate part I, fields 2.1 and 2.2. In documents of the older form they were at positions 2 and 3.
Is the key number unique to a vehicle?
No. It names a type with variant and version. All vehicles of the same version share the number.
Can I derive the VIN from HSN and TSN?
No. The path only runs one way: from an individual vehicle you can derive its type, from a type you cannot derive the individual vehicle.
Why does my key number return several engine variants?
Because one type approval can cover several variants and versions. Precise assignment needs additional data, in case of doubt the VIN.