A “flow transformer” will be fitted directly in front of the air mass sensor on the 1.6-litre EA 189 engine. This is a mesh that calms the swirled air flow in front of the air mass sensor and will thus decisively improve the measuring accuracy of the air mass sensor. The air mass sensor determines the current air mass throughput, which is a very important parameter for the engine management for an optimum combustion process. In addition, a software update will be performed on this engine. The time needed for the implementation of the technical measures is expected to be less than one hour.

The first outcome of those efforts has now arrived in the form of a technical measure to be applied to the 1.6-litre engine. Here’s Volkswagen’s official explanation for the modification:

Here’s the moment VW diesel owners have been waiting for. The under-fire manufacturer has just revealed how it intends to fix the Europe-based diesel engines that were found to feature a ‘defeat device’ , which would trick testing equipment into reading low nitrogen oxide (NOx) levels. The company has been working on 1.2-, 1.6- and 2.0-litre versions of the EA 189 engines to find ways to bring NOx levels below the regulatory limit, while targeting no “adverse effects on the engine output, fuel consumption and performance.”

The upgrade has been accepted by the Federal Motor Transport Authority, and Volkswagen is currently in the process of figuring out the recall process for each European country. The first batch of recalls are expected to start in January 2016, while the rest of the engines are expected to be sorted by the end of the year. VW has also promised to provide a courtesy car to anyone who requires one while the work is being carried out, however it shouldn’t take more than an hour to fit the part.

As for the 2.0-litre engine, customers will be able to pop into their dealer once the recall has been issued to receive a free software update. The same is expected for 1.2-litre variants, but VW is waiting for confirmation of this. If you’re the owner of one of the VW Group’s other affected brands - Audi, Seat and Skoda - you can expect similar information soon.

Although Volkswagen is targeting no adverse effects on the car’s economy or performance, it says that the different applications of the engines across its range mean that it can’t confirm whether it has achieved this yet. It’ll be interesting to see exactly what effect these measures will have in the real world, and more importantly for the bean counters, whether owners start ditching the brand when it’s time to get a new car.