U0441: Données non valides reçues des informations de commande critiques pour les émissions
Que faire
This is one of the few codes on your car that is about paperwork rather than mechanics, and the car may drive perfectly.
Every computer that affects emissions carries a software calibration, and a number calculated from that software which the car will report to anyone who asks. It exists so an inspector can confirm the emissions software has not been altered. This code means that check has failed.
Three things cause it. A software update that did not complete properly — usually because battery voltage dropped part-way through. A replacement module programmed for a different vehicle or version. Or emissions software that has been altered: a remap, a performance tune, a particulate filter or EGR delete, an AdBlue emulator.
Whichever it is, expect an emissions test failure — and know that clearing the code does not help. The tester reads the calibration number out of the computer itself, not out of the fault memory, so it is still there after any reset.
If the car has been remapped or tuned, including by a previous owner, say so. It saves a great deal of wasted diagnosis, and the only fix is putting the manufacturer's original software back. If it has not been touched, and this appeared after a dealer visit or a module replacement, it is most likely a reprogramming problem, and repeating the update properly is the usual answer.
Ce que signifie ce code
A module is reporting emissions-critical control information that does not verify. See U0400 for what distinguishes this family from lost communication — but note at the outset that this is the one member of it that is usually not a wiring fault at all.
Every emissions-related module carries a calibration — the software and data that decide how the engine fuels, how it manages the aftertreatment, and what it reports to a tester — and every calibration carries a number computed from its own contents. That is the calibration verification number, and the vehicle publishes it on request alongside the calibration identifier. It exists for exactly one purpose: so that anybody can check the emissions software has not been altered.
So this code is not a sensor complaint. It is an integrity check that has failed. Either the emissions-critical information a module holds does not match its own checksum, or one module is receiving emissions-critical data from another that does not verify against what it expects.
Three things produce it, and separating them matters because two are innocent.
- A programming session that did not finish. Reflashing takes minutes at a steady voltage, and a battery that sags, a charger that was not fitted, or a session that dropped leaves a calibration only partly written. The module usually still runs, which is what makes this confusing.
- A module that is not the vehicle's own. A second-hand replacement carrying another car's calibration, or a new one programmed to the wrong variant, verifies against the wrong number.
- Altered emissions software. A remap, a performance tune, an EGR or particulate filter delete, a reductant dosing emulator — anything that rewrites or intercepts emissions-critical data changes what the checksum covers.
The consequence is regulatory rather than mechanical, and that is what makes this page necessary. The vehicle may drive perfectly and show no symptom whatever. But the readiness monitors will not complete, and an inspection reads the calibration number out of the module rather than out of the fault memory — so clearing the code does not clear the finding. Where the test checks it, the vehicle fails with nothing visibly wrong under the bonnet.
Worth saying plainly and without judgement: if the vehicle has been tuned, no amount of diagnostic work clears this while the altered calibration is in place. The remedy is the manufacturer's original software, and a workshop should say so rather than start replacing parts.
The reverse deserves saying too. A car that has never been touched, showing this after a dealer software update or a module replacement, is very probably a programming problem — repeat the flash properly, on a charger — and not evidence of anything at all.
Causes probables
Commencez ici
- Moteur reprogrammé ou logiciel non d'origine installé · spécialisée
- Programmation du calculateur interrompue · spécialisée
- Calculateur d'occasion verrouillé sur un autre véhicule · spécialisée
- Calculateur non codé au véhicule · spécialisée
Moins fréquent
- Logiciel du calculateur corrompu · spécialisée
- Logiciel mis à jour sur un seul calculateur · spécialisée
Symptômes
Composants concernés
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