Skip to content
Lion Yard Trading
Mercedes-Benz · Exhaust & Emissions

SCR catalyst

The catalyst where AdBlue and exhaust gas react to break nitrogen oxides down into nitrogen and water.

Also called SCR, NOx catalyst.

How you know it is this

  • A NOx conversion efficiency fault
  • An emissions warning with a countdown to no-start
  • Failed emissions at registration

Worth knowing before you buy

  • BlueTEC and later diesels only. A petrol car has no SCR.
  • Usually fails because of AdBlue crystallisation or a dosing fault rather than the catalyst itself. Check the injector and the pump first.
  • Expensive. Confirm the diagnosis before ordering, because the cheap causes look identical from the dash.

What we need to quote it. The engine code and the fault codes. The chassis number settles the generation, the body and usually the engine in seventeen characters — it is on your mulkiya. A photograph of the old part helps where there is more than one version.

EGR valve and coolerLambda sensorsCatalytic converterParticulate filterDifferential pressure sensorTemperature sensorsSCR catalyst
After-treatment — schematic, to show where the part sits. Arrangement is right; it is a diagram and not a fitment reference.

Rest of the after-treatment

All exhaust & emissions parts
Get in touch

SCR catalyst for your Mercedes-Benz?

Send the chassis number and a photograph of the old part. We come back with genuine, OEM and aftermarket options priced side by side, with lead times.

Mon–Sat, 8:00 AM – 6:00 PM · +971 54 303 3119 (Operations Director) · +971 54 241 0599 (Managing Director)