Almost all slightly newer diesel cars use a so-called SCR catalyst for nitrogen oxides, which requires refueling with a urea additive called AdBlue.

These diesel vehicles are easily identified by looking at the fuel tank next to the cap.

That is, if there is a smaller blue AdBlue tank cap next to the diesel hole, the car also has an SCR catalytic converter.

How much will it cost to rebuild all the particle traps and catalysts of such a new-generation three-stage purification system in time, and how typical is the sudden, perhaps rather expensive need for renewal of the whole system?

Björn Boström, Diesel expert at Diagno Oy, Heikki Parviainen, Lecturer in Vehicle and Mechanical Engineering at Metropolia University of Applied Sciences, Juhani Laurikko, Senior Research Fellow at VTT, and Traficom, the Finnish Transport and Communications Agency, and SATL together together as follows:

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“It is likely that the entire system will need to be replaced, mainly in the event that the only available spare part covers the entire exhaust module with its particulate filters and catalysts.

In many cases, however, the entire package does not need to be renewed for a single defective catalyst alone.

It is also very rare for the whole system to be damaged and therefore to be rebuilt.

A crashed car that has suffered physical damage is a certain thing in itself.

Today, the technique has often been combined, for example, so that the first catalyst is both an oxidation catalyst and a storage nitrogen oxide catalyst.

The latter component, in turn, is a particulate filter with a coating of SCR catalyst.

Thus, there are fewer physical catalysts than functional purification techniques.

This does not necessarily lower the price of an individual spare part, but the total cost is lower.

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Catalyst technology has also proven to be quite reliable.

Maintenance is mainly required by a particulate filter, which has a service or replacement interval set in many cars.

To determine the exact price, you should know at least the make and model of the car.

In passenger cars, a particulate filter alone costs a few hundred at its cheapest


Replacing an entire catalytic converter system, if needed, is likely to cost thousands of euros, depending on the make and model of car.

However, the price for heavy equipment is higher than mentioned, because the catalysts are larger there, ie they contain more expensive precious metals. ”

Source: Finnish Automotive Technology Association (2020): Questions about diesel cars - SATL experts answer.