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Last reviewed: 6 July 2026
V55/5 form · Box 42
HC + NOx (g/km)
What goes in box 42
Box 42 of the DVLA V55/5 form is for hc + nox (g/km).
The combined hydrocarbons + NOx figure — usually only shown for diesel vehicles. Take it from the Certificate of Conformity; on EU registration certificates it's field V.4. Leave blank if you don't have this information.
What to enter
| Field | Type | Required? |
|---|---|---|
HC + NOx (g/km) The combined hydrocarbons + NOx figure — usually only shown for diesel vehicles. Take it from the Certificate of Conformity; on EU registration certificates it's field V.4. Leave blank if you don't have this information. | number | Optional |
Source
This page is generated from the same field definitions our V55/5 tool validates against, mapped to the official DVLA guidance.
V355/5 official guidance (GOV.UK)v55-5.com is an independent service and is not affiliated with the DVLA.
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