Volkswagen EA288

The EA189's replacement and the Volkswagen Group's current four-cylinder diesel, in 1.6 and 2.0 litre forms. It is a different engine family despite sharing displacement and badge with what it replaced — which matters because the EA189's emissions history does not transfer to it, and treating a 2016 2.0 TDI as an EA189 is a common and consequential mistake.

The emissions hardware is the substance of the diagnostic picture: SCR with AdBlue injection on most applications, plus a particulate filter and cooled EGR. That adds a whole class of fault the older engine did not have — reductant quality, injector crystallisation, tank heater and NOx sensor failures — and the corpus's P20xx and P2Bxx reagent codes describe exactly this territory.

As with any modern diesel, the recurring background cause is duty cycle rather than a component: an engine that never reaches temperature cannot regenerate its filter, and the resulting cascade looks like several independent faults at once.