Volkswagen EA189

The common-rail diesel family fitted across the Volkswagen Group through the late 2000s, in 1.2, 1.6 and 2.0 litre forms — so the displacement is a property of the variant, not of the family, and a 1.6 EA189 and a 2.0 EA189 are different engines sharing a design.

This is the family at the centre of the 2015 emissions case, in which engine-management software detected test conditions and altered emissions behaviour accordingly. That is diagnostically relevant rather than merely historical: many of these engines received a mandated software update, and some owners report driveability and EGR complaints dating from it, so the service history around 2016–2018 is worth establishing before treating a running fault as original.

Mechanically, the EGR cooler, the diesel particulate filter and — on higher-mileage examples — the oil pump drive are the recurring themes. Short-journey use is the common thread behind most filter and EGR complaints, and asking how the car is driven is often more diagnostic than another scan.