Common eCoC Pitfalls: XML Validation Errors, Signature Problems and How to Sidestep Them
Why eCoC submissions get rejected
The VCA eCoC system runs automated validation on every submission, and any file that fails the XSD schema check or carries an invalid digital signature is rejected on the spot. Knowing the most common ways things go wrong — and putting processes in place to head them off — is key to a smooth transition.
The pitfalls that trip people up most
1. Changing the XML formatting after signing
This is far and away the most frequent reason signatures fall over. Once an IVI XML file is digitally signed, any edit at all — a single whitespace character, a line break, or a reformat of the XML — breaks the signature. Always sign files as the very last step before submission.
2. The wrong approval authority codes
UK eCoCs have to carry the right approval authority code: g11 for GB type approvals or n11 for UK(NI) approvals. Reach for an EU code (e11, say) or leave the code out altogether and the file is rejected.
3. Missing required fields
The IVI schema runs to hundreds of fields, plenty of which are conditionally required depending on vehicle category and build stage. A field that's optional on a base vehicle can be mandatory on a completed one, and omitting just one required field fails the XSD check.
4. Data type mismatches
Text dropped into numeric fields, dates in the wrong format, or masses with the wrong decimal precision will each throw an XSD validation error. The data has to match the schema-defined types precisely.
5. Expired or invalid signing certificates
A digital signature needs a valid certificate from a recognised trust service provider. Expired certificates, self-signed ones, or certificates from providers that aren't recognised will all cause signature validation to fail.
6. Inconsistent multi-stage data
In multi-stage builds, the completed vehicle eCoC has to reference the correct base vehicle data. Any mismatch in VINs, type approval numbers, or stage references between the base and completed vehicle eCoCs gets flagged.
How to steer clear of these pitfalls
- Always run the XSD schema check before you sign
- Never touch a file after digital signing — make signing the last step
- Make the most of the testing period (March–July 2026) to submit test files and surface issues early
- Automate the generate → validate → sign → submit pipeline to wipe out manual errors
- Keep an eye on certificate expiry dates and renew in good time
eCoC EU² designs out the common errors
eCoC EU² software automates the whole eCoC pipeline, stripping out the manual steps where most errors creep in: