# BR-CL-07 Object identifier scheme must come from UNTDID 1153

When the invoiced object identifier (BT-18) has a scheme identifier (BT-18-1), the scheme must be a reference qualifier from UNTDID 1153.

## Problem Description

> **ERROR**: EN 16931 code-list rule (BR-CL)

## Context and Significance

BT-18 identifies the object the invoice is for, such as a vehicle, a meter or a subscription. In UBL it is cbc:ID/@schemeID in a cac:AdditionalDocumentReference with cbc:DocumentTypeCode 130; in CII it is ram:ReferenceTypeCode in a ram:AdditionalReferencedDocument with ram:TypeCode 130. The rule fails when an ERP writes a label such as "VEHICLE" or "ORDER", or a lowercase code, as the scheme. Example: a leasing invoice for a car uses schemeID="ABZ" with the licence plate as the value.

## Solution

Set the scheme of BT-18 to a UNTDID 1153 qualifier in capital letters that describes the object, e.g. ABZ (vehicle licence number). If no qualifier fits, omit the scheme identifier instead of inventing a code. An order number belongs in BT-13, not in BT-18.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-CL-07)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-CL-07)

## Valid Examples

- BT-18-1 = ABZ — licence plate of the invoiced vehicle
- BT-18 without a scheme identifier — the rule does not apply

## Invalid Examples

- BT-18-1 = VEHICLE — free-text label instead of a code
- BT-18-1 = abz — lowercase; codes are case-sensitive

## Code Examples

### Valid XML
```
<cac:AdditionalDocumentReference>
  <cbc:ID schemeID="ABZ">AB-123-CD</cbc:ID>
  <cbc:DocumentTypeCode>130</cbc:DocumentTypeCode>
</cac:AdditionalDocumentReference>
```

### Invalid XML
```
<cac:AdditionalDocumentReference>
  <cbc:ID schemeID="VEHICLE">AB-123-CD</cbc:ID>
  <cbc:DocumentTypeCode>130</cbc:DocumentTypeCode>
</cac:AdditionalDocumentReference>
```

## Affected Fields

- [BT-18-1 Invoiced object identifier scheme identifier](/resources/xrechnung/bt-18-invoiced-object-identifier)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.