What exactly is a NOx sensor and what does it do?

With the introduction of N43 and N53 series engines in 2007, BMW began to incorporate more sophisticated technology into the marque’s basic specification models. One of these new developments for these motors was a new engine management computer – called a DME in BMW terminology – as well as a development of their variable valve timing tech.

The sensor, mounted on the exhaust system before the catalytic converter, measures the level of nitrogen oxide (i.e. NOx) to feedback data to the engine’s computer so adjustments to valve timing and fuel mixture can be made. Traditional combustion engines without this technology would simply have the same fuel mixture for all conditions, making them compromised and less efficient than they could be.

The double-edged sword of these new innovations is that whilst these systems mean that the N43 and N53 series engines produce more power and burn less fuel than the outgoing units, these NOx sensors have proved prone to failure. Here are the key symptoms of NOx sensor failure for these engines.

Increased fuel consumption

Without information from the sensor, the engine management software cannot accurately work out how the engine is running in terms of the fuel mixture and air-to-fuel ratio. As a result, this causes the engine’s electronic brain to assume a worst-case scenario and make the fuel mixture run rich (increased amount of fuel) to ensure maximum power in poor conditions. If you find that your fuel economy drops during regular driving, this could be a tell-tale sign of a faulty sensor.

Unstable and erratic idle

One of the tell-tale signs of a faulty nitrogen oxide sensor in an N43 or N53 powerplant is an unstable engine speed at turnover. The fuel injectors have to keep a certain flow of fuel into the combustion chambers at idle, a task that is electronically managed by the DME. But with a faulty sensor, surging and starving of the fuel can result in an uneven idle (instead of ticking over at around 800-1000rpm)

Engine warning lights

Although the NOx sensor itself is not mounted in the engine bay, component failure will likely result in an engine warning light. This, of course, is not the most specific indicator of a NOx sensor giving way, but it paints a clearer picture if your car is also experiencing the previously mentioned warning signs.

All above explained problems are the most commons NOx sensor symptoms for BMW 116i, 320i, 523i 528i 530i 325i 325xi 330i 330xi and other engine models.

Below you will find bmw and continental parts numbers available at our  shop.

In addition it might trigger AdBlue-System fault on the dashboard and iDrive screen.

BMW nox sensor errors and explanations

Error codes related to BMW NOX sensor:

  • 2AEC Nitrogen Oxide Sensor Self Diagnostics
  • 2AF0; 2B05 nitric oxide sensor, heating
  • 2AF2; 2B06; 2B09 nitric oxide sensor, Lambda linear
  • 2AF4; 2B07; 2B0A NOx sensor, electrical
  • 2AF6; 2AFB; 2B0B nitric oxide sensor, Lambda binary
  • 2AF9 nox sensor, nox signal: coast mode check
  • 2EAE NOx sensor message missing (timeout)
  • 30D6 nitric oxide sensor, plausibility
  • 30D8 NOx sensor, Sensor damaged
  • 30DA NOx sensor, heating time
  • 30DC nitric oxide senor, heating
  • 30DE NOx sensor – Lambdaprobe before catalyst, Korrelation
  • 30E0 NOx sensor, Offset
  • 30E2 nitric oxide sensor, thrust test
  • 30E4 nitric oxide sensor, aging
  • 30E6 nitric oxide sensor, dynamics
  • 2AC600 SCR System efficiency: Efficiency too low in area 3
  • 26F500 SCR System efficiency: Efficiency too

A list of available NOx sensors at Xenons4U

  • 759040204 5WK96650B - 5WK96650C
  • 759040202 5WK96650
  • 758712905 5WK96610K
  • 758712903 5WK96610L
  • 758712901 5WK96610G
  • 758051801 5WK96610D
  • 758712902 5WK96610H
  • 758712905 5WK96610L
  • 11787587129
  • 11787587130
  • 758713001 5WK96621F
  • 758713005 5WK96621J
  • 758713003 5WK96621H
  • 758713002 5WK96621G
  • 758713005 5WK96621K
  • 758051701 5WK96621C
  • 758232601 5WK96621D
  • 758712701 5WK96621E
  • 857647101 5WK96699B
  • 8580410-03 0281007018/19
  • 8580410-01 0281006556
  • 851879101 5WK96699A
  • 858984401 5WK96697C 13628589844
  • 857646901 5WK96697B
  • 858984601 5WK96699C
  • 851878901 5WK96697A
  • 851166601 5WK96699
  • 851166401 5WK96697
  • 759040205 5WK96650D
  • 758713004 5WK966 5WK96621

Below you will find a list of BMW cars, which are using our listed sensors, to make sure we have correct part for your car we will need to get a picture of your old part or at least part number bmw or either continental, siemens vdo.

  • 1 Series E81 2006, 2007, 2008, 2009, 2010, 2011
  • 1 Series E87 LCI Facelift 2006, 2007, 2008, 2009, 2010, 2011
  • 1 Series E88 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
  • 1 Series E82 2009, 2010, 2011, 2012, 2013
  • 1 Series 116i, 118i, 120i
  • 1 Series F20 F21
  • 2 Series F22 F45
  • 3 Series E90 2007, 2008
  • 3 Series E91 2007, 2008
  • 3 Series E90 LCI Facelift 2008, 2009, 2010, 2011
  • 3 Series E91 LCI Facelift 2008, 2009, 2010, 2011, 2012
  • 3 Series E92 2006, 2007, 2008, 2009, 2010
  • 3 Series E92 LCI Facelift 2010, 2011, 2012, 2013
  • 3 Series E93 2006, 2007, 2008, 2009, 2010
  • 3 Series E93 LCI Facelift 2010, 2011, 2012, 2013
  • 3 Series 316i 318i 320i 325i 325xi 330i 330xi
  • 3 Series F30 LCI Facelift 2014, 2015, 2016, 2017, 2018
  • 3 Series F31 LCI Facelift 2015, 2016, 2017, 2018
  • 4 Series F32
  • 5 Series E60 E61 Facelift LCI
  • 5 series F10 F11 F07 GT G10 G11
  • 5 Series 520i 523i 525i 525xi 530i 530xi
  • 5 Series F10 2010, 2011, 2012, 2013
  • 5 Series F11 2010, 2011, 2012, 2013
  • 5 Series G30 G31
  • 5 Series: 523i 528i 530i N53
  • 6 Series E63 E64 Facelift LCI
  • 6 Series 630i
  • 6 Series F12
  • 7 Series F01 LCI Facelift 2013, 2014, 2015
  • 7 Series G11
  • X5 E70 2007, 2008, 2009, 2010
  • X5 E70 LCI Facelift 2010, 2011, 2012, 2013
  • X5 F15 2012, 2013, 2014, 2015, 2016, 2017, 2018
  • X6 F16 2013, 2014, 2015, 2016, 2017, 2018
  • X3 F25 2013, 2014, 2015, 2016