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Mercedes-Benz · Exhaust & Emissions

NOx sensors

The sensors measuring nitrogen oxides before and after the SCR catalyst, so the car knows how much AdBlue to dose and whether it worked.

Also called NOx sensor.

How you know it is this

  • A NOx sensor or conversion efficiency fault
  • An emissions warning with a no-start countdown
  • Limp mode

Worth knowing before you buy

  • One of the most common faults on a BlueTEC diesel, and expensive for a sensor.
  • There are two, upstream and downstream, and they are different parts. The code names which.
  • Each has its own control module in the plug and usually needs coding to the car.
  • Before ordering, confirm it is the sensor and not the dosing valve — both throw efficiency codes.

What we need to quote it. The engine code and the fault code naming the position. 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.

AdBlue tank and heaterLevel and quality sensorPump and moduleDosing valveNOx sensors
AdBlue dosing — schematic, to show where the part sits. Arrangement is right; it is a diagram and not a fitment reference.

Rest of the adblue / scr

All exhaust & emissions parts
Get in touch

NOx sensors 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)