Active Dpf Regen During Mot

[Dieseldonkey]

Van turns 3 at the end of the month, so had it's first MoT done today. It dawned on me that I'd put a bottle of Redex in when I last filled it up and wondered if it would effect the hydrocarbon emission test. Needless to say it passed without issue.

However, got me thinking. What happens if an active regen kicks in during the test? Does the extra fuel being burnt cause an issue?

 

[Pauly]

It must have an effect as the engine timing is altered to push exhaust temps up significantly
I suppose it depends how clean everything is burning with retarded timing ?
I think MOT testers must have an understanding of this wizardry