In several entries, I have stated that in the “civilized world”, only NTK has mastered the NOx sensors’ technology. NOx sensors are manufactured exclusively by the Continental group, which has bought Siemens VDO with their developed technologies and products. So this is no surprise that for ancient NOx sensors, Siemens VDO is indicated as a manufacturer, but for newer ones – Continental.
Lately, I have received messages from several readers of the blog that there are also “alternative” NOx sensors available in the market offered by Metzger. I associate Metzger autoteil with (re)selling and (re)packing of the cars’ spare parts. Maybe there has been a quiet and imperceptible revolution in the industry? Besides, these sensors are not cheap; their prices are around EUR 350 – 400+! Before revealing this secret, a short story regarding the experience of a BMW user.
When seeing the typical error messages regarding the NOx sensor (2AF2; 2AF4; 2AF6), the car owner has purchased and installed a Metzger sensor. Two weeks after installing, the error message list indicated:

Here, the mismatch of Lambda values, also the error message regarding the control probe, 2-nd bank. Needless to say, that this is an N43 series engine, which does not have such a probe at all! The vehicle owner replaced all (three) Lambda probes, the error message 2C7F (also the two other error messages) did not disappear.
Let’s see live data:

Incorrect values marked with red. There is not much to comment on – all live data are completely incorrect! The sensor is damaged.
The situation is made even worse because all injectors are working correctly – no leaking, no misfires, no other problems, which could be blamed for damaging the sensor, are not observed.
Unfortunately, EUR 400, spent on the purchase of the sensor, is wasted.
And now I’m returning to the beginnings – new participant of the NOx sensor market.

This is the package in which Metzger offers the NOx sensors.
I spend quite a lot of time on the internet, trying to find the pictures of these sensors’ bottom sides. There I hoped to find more information regarding the manufacturer.
Unfortunately, the only way to get such an image is to study panorama pictures of 360 degrees:

Really? The sensor, EUR 400 worth, even has no barcode? No information regarding the manufacturer? No other data – batch number, manufacturing date, identification of the release? No QC control label? How are these sensors sorted and stored at the factory? How are they counted? When seeing such an image, my diagnosis is harsh – unfortunately, these are “analogs” from China.
The Chinese manufacturers offered me such “analogs” for a price of 70 .. 80 USD/piece (when buying 10+). Well, you can count the margin by yourself. An excellent product! Additionally, Metzger addresses the customers, who avoid too cheap products, because they understand that there could be nothing good for EUR 150 .. 200. But for EUR 400? It turns out – the same, but for a higher price!
Finally, a note – unfortunately, E series vehicles (which are equipped with N43/N 53 series engines) are at least 10 years old. Their NOx catalytic converters, with a probability of 99%, are aged. Installing the OEM NOx sensors is useless – the DME will record the error message 30E9 (reduced performance of the NOs catalytic converter); Stratified charge will be turned off, and… the investment in the OEM NOx sensor will turn out completely useless.