Common mistakes when generating the DeCA (and how to avoid them)

A DeCA (Documento electrónico de Control Administrativo) can have all its data right and still not comply, because of how it was generated, delivered or corrected. These are nine mistakes that make it invalid or non-compliant, with the rule they break and how to avoid them. The rules come from the technical resolution of 5 June 2026 (Resolución de 5 de junio de 2026) and Order FOM/2861/2012 (Orden FOM/2861/2012).

Mistakes in the file and the link

1. Scanning a paper document

Scanning a form filled in by hand does not produce a DeCA. Section two (apartado segundo) of the Resolution requires generation to be “native digital” (our translation), from the application’s structured data, and makes it clear: “Electronic files obtained by scanning an existing paper document or from digitised images shall therefore not be valid”.

How to avoid it: generate the PDF with an application that builds it from the data. Printing that PDF for the driver is allowed; what does not work is the other way round.

2. A link with a password or a download button

The DeCA’s QR contains the URL from which the officers download the PDF. Under section three, “no URL shall be valid that leads to a web page requiring credentials or authentication, or that incorporates download buttons or other elements involving manual interaction”. In addition, under point 2 of the same section, the link cannot expire before the service ends.

How to avoid it: scan the QR with a phone that is not logged in and check that the PDF downloads directly. The technical details are in the DeCA’s QR code (in Spanish).

Timing and delivery mistakes

3. Creating the DeCA when the lorry has already left

Section one requires the data to be turned into the file “as soon as they are known and always before the effective start of the service”. To guarantee this, the application must record the date and time of creation, and section two requires them to appear as metadata of the PDF. The Resolution says no more, but we infer from this that a DeCA created halfway through the journey would carry, in the file itself, the time that gives it away.

How to avoid it: generate the DeCA as soon as you have the load details and give the driver the copy before leaving, as section seven requires.

4. Correcting the printed copy by hand

The driver may carry the DeCA printed, always with the QR, but crossing out a number plate or changing a weight in pen does not work. Section seven says: “handwritten notes on it shall not be taken into account. The only valid way to modify a DeCA is the one indicated in section five of this resolution”.

How to avoid it: make any change in the application, using one of the two methods in section five. We explain it in how to modify a DeCA.

5. Modifying the DeCA and not resending it to the driver

Section five allows two methods: editing the existing PDF (same URL and same QR, adding the reason for the change and marking the old data as no longer valid) or generating a new one (new URL and new QR, keeping the original). And it concludes: “In both cases, the modified PDF or the new PDF must be delivered to the driver”. With the second method, moreover, the copy the driver carries has a QR that points to the previous file.

How to avoid it: treat resending as part of the modification, not as a separate step.

Data mistakes

6. Only the tractor unit’s plate, or a vehicle change not recorded

For an articulated vehicle, article 6 g) of the Order requires “both the registration number of the tractor vehicle and that of the semi-trailer or trailer towed by it”. And it adds: “If, once the transport operation has begun, a change of vehicle occurs, this circumstance must be recorded in the control documentation by the transport company”. Under article 7.3, the effective carrier (transportista efectivo) answers for this data.

How to avoid it: check both plates before leaving and, if the vehicle changes, modify the DeCA and resend it.

7. Grouping consignments with a different shipper or carrier

A DeCA can group several consignments (envíos), but section six only allows it “when the contractual shipper [cargador contractual] and the effective carrier are the same for all the consignments”. Each consignment must have its origin and destination and the nature and weight of its goods identified.

How to avoid it: if on the same route you carry consignments for two different contractual shippers, make a DeCA for each one.

8. Not identifying the two parties separately, or thinking the CMR format makes it a CMR

The format is free, including that of a consignment note (carta de porte) or an ADR document. But section eight requires that “the roles of contractual shipper and effective carrier are always identified expressly and distinctly”. They are not always the same people as the shipper (cargador) and the carrier (porteador) of the consignment note: according to question 9 of the FAQ published by Spain’s Ministry of Transport (Ministerio de Transportes y Movilidad Sostenible), if a carrier subcontracts to another, the first is the contractual shipper and the second, the effective carrier.

Question 13 also separates the format from the legal nature: in a national transport operation “the CMR format may be used if it is more convenient, but that does not mean the service is being performed under the CMR Convention, since it does not apply to national transport”.

How to avoid it: label the boxes “contractual shipper” and “effective carrier” and include all the data in article 6. More in DeCA and CMR (in Spanish) and in who makes the DeCA when transport is subcontracted.

Mistakes after the service

9. Not keeping the DeCA for a year

Article 9 of the Order requires the document to be kept “for at least one year” at the disposal of the Land Transport Inspectorate (Inspección de Transporte Terrestre), and section two of the Resolution applies this to the electronic files of both the contractual shipper and the effective carrier. If one of the two generated them, it is enough for the other to be able to download them during that year.

Do not confuse this with the link: once seven calendar days have passed since the end of the service, download via the URL can be deactivated (section three), but the file is still kept. If you modified the DeCA by generating a new one, keep the original as well.

How to avoid it: check how long your tool keeps the PDFs.

What depends on the tool and what depends on you

Mistakes 1, 2 and 9 are avoided or caused by the application you generate the DeCA with: check them when choosing it, using the list of DeCA requirements. The rest depend on the way you work: generating in time, handing over the copy before leaving, correcting only from the application and always resending.