[problems]

Correct me if I'm wrong, but most regular consumer vehicles aren't required to have a urea/DEF system, but all the big trucks and commercial vehicles tend to.

Somebody was blaming this on trucks, but I'm thinking this might be the opposite - their small cars as it was with VW because they don't have these sorts of systems in place.

[Reason077]

You're right. It's now light diesel vehicles that are the primary problem with regard to excessive NOx emissions. At least in Europe, where there are a huge number of light diesel vehicles on the roads.

But there are, of course, a lot of old pre-DEF heavy vehicles on the roads too that would not comply with modern emissions standards.

[djrogers]

The engine in question did have a DEF system though...