This entry is a dedication to those users who ask me for advice after “everything is already done”. The questions are quite similar – what can I do? Why so? Why did everything go wrong?
I will note that I am not fighting the competitors because NOXEM is intended for situations when/if the NOx catalytic converter is already aged. In this case, OEM NOx sensors can not be used anymore. I have no reason to defame the seller, who works in a different segment.
The OEM NOx sensor “head” replacement could be used, for example, for the F series diesel engines, which are equipped with AdBlue, or for those few N53 of F series, for which the NOx catalytic converter is theoretically as if in the work order.
On eBay, you can find several sellers who sell the replacement head for these NOx sensors.
Here, the example:

I hid the seller’s name because, as I already mentioned, I have no intention to defame any specific vendor. The entry is dedicated to the situation as a whole.
Here I still have to mention that the specific vendor’s name contains an “OE” letter combination, which gives additional reliability – as if it sells “original equipment”. The image is also decorated by the marking “genuine parts” – looks impressive!
And even more – this spare part has a two-year warranty! Isn’t it great?

Here, the manufacturer of the spare part is NTK.
Note: NTK (the company of the Continental group) is the only known to me (if we are not counting “trials” of China) manufacturer of the NOx sensors. As far as I am informed, NTK has never sold the sensor “head” separately. It has several reasons:
a. the sensor can not be used without a specific management system. The management system is ensured by the electronic module of the sensor, which also is manufactured by the companies of the Continental group:
b. each sensor (its “head”) has to be calibrated by several parameters. After assembly of the electronics and connection of the current sensor, the electronic module is switched to the service mode (in a way known only to the manufacturer), the sensor is placed in the environment of the exact air composition, the calibration of the sensor is performed. Without this calibration, the performance of the sensor is very inaccurate.
Also, visually this sensor does not remind of NTK head. This head looks 1:1 as the China “analogs”, which are sold by several tenths of EUR by different China vendors.
Let’s see what else the vendor is saying regarding the sensor:

What please? N42/N46? It looks that the seller has not the slightest clue what he is selling! These engines have never had the NOx sensors!
Probably, you will argue – everything looks excellent! This seller has 100% positive feedback!
Besides, the seller is proudly presenting them in additional images. What could be wrong here?
You have to take into account several conditions:
a. significantly largest number of buyers leave the feedback (if leaves it at all) directly after receiving the shipment. Receiving the probe packed in the plastic bag – why not leave positive feedback? Has the user had any possibility to check the performance of the probe? No, he hasn’t!
b. installation of the probe takes time. The old sensor has to be dismantled; the new probe should be soldered, etc. I doubt that anyone is waiting to leave the feedback after installation;
c. even if the probe is installed, in 99% of cases (which relates to BWM), not the users, not even the service centers know how the readaptation of the engine should be performed or how to check the performance of the sensor (if it sends correct data), or how to check, does the engine uses Stratified charge or not. The only criteria: there is or isn’t the error message exactly for the NOx sensor. Unfortunately, there can be no error message for the sensor performance! First – issues to complete the self-test procedures (which is very plausible in the case of installing such sensors from China). Other problems (for example, reduced performance of the NOx and CO catalytic converters, etc.), due to which the DME is not using a Stratified charge. Also, in this case, the error messages regarding the NOx sensor will not appear because DME will not even try to switch ON this sensor.
d. if this repair technology is used for BMW vehicles equipped with AdBlue (they have 2pcs of NOx sensors – before and after the NOx catalytic converter), there is a large possibility there will be error messages recorded for all possible things – for the Offset of dynamics indications of the second sensor, for the injection of the AdBlue system (its performance), etc. Such inaccurate sensor head parameters are so different from the perfect ones that DDE cannot correctly identify the damaged hub. The precision and the coherence (coincidence) of the NOx sensor indications are especially marked in the aftersales materials of the BMW AG.
I am returning to the N43/N53 series engines.
You will install the probe; there is no error messages recorder regarding the NOx sensor, but – the engine still is not using the Stratified charge! True thou, you will find it out only after a long time, performing the diagnostics via Bimmerprofs. Even if the error messages appear after a short time, you have no option to give repeated feedback on eBay.
The loud slogan regarding the warranty of 2 years sounded for me double-suspicious. Why? It has to be understood that the NOx head can be damaged by the fuel, the water condensate, also by mechanical hit. The NOx probes are very fragile – even slightly increased oil consumption, slightly leaking injectors, a slight hit by the stone on the exhaust is fatal to it. I tried to contact this current vendor several times. I asked for more exact information regarding this warranty. Unfortunately, the vendor didn’t answer anything for me. Even if the communication itself (without illusions: it’s like that with any customer – I am not special with anything) is performed in such a manner, it is clear that the promised warranty is only “on paper”.
Should admit, not a bad business- selling the China “analogs” with a margin of 500 .. 1000%, plus receiving positive feedback. Unfortunately, at the moment, when the buyers of such a “head” approach me with a question, “why so, and what to do” – I actually have no suggestions. Unfortunately, the attempts to “get through” cheaply usually finishes with no positive results.
Note: the original NTK probe has a body of a different shade of metal; no model markings on the body; the additional insulation of the wire is embedded in the body, not simply put on.
Do not expect any wonders from the fakes!