Between `2016` and `2019`, the `S4 Avant B9` takes a very specific path on the European market: a quick `S` estate driven mainly by the `3.0 TDI V6` with `48 V` mild-hybrid support, more torque-rich than theatrical. Against a BMW 3 Series, it leans less on noble-engine image than on cruising speed, traction and genuine versatility. On the used market, that recipe can be excellent to live with, but only if modern diesel maintenance was genuinely understood.
The engine to read first is the `3.0 TDI EA897 evo2` in `DEWB` form, paired with `tiptronic`, `quattro` and the `48 V` network. On this phase, you need to look closely at `EGR`, `DPF`, `AdBlue`, cooling, the `12 V` battery, the `48 V` starter-generator, restart quality, the condition of the heavy running gear and software coherence. The car can absorb high mileage if it is driven regularly and if fluids, emissions systems and electronics have not been left behind.