This document is a short summary of basic topics that you need to know regarding NOXEM and the specifics of your car’s engine:

  1. The correct performance of the NOx system is critically important for the N43/N53 series engines. Read more here. Why exactly the N43/N53 series engines cannot work properly without the Stratified charge? Read here.
  2. It is very important to update the DME software (to the latest release/ZB) for N43/N53 series engines. It is critical – especially for N53 series engines. For N53/MSD80 series engines BMW AG has developed a special smoothness improvement upgrade called DIRU. Read more here.
  3. N43/N53 series engines cannot be correctly “tuned” to run on ethanol, LPG, diesel fuel, electricity, or atomic energy. Unfortunately, there are zero positive examples of “chip tuning,” too. If your car is equipped with N53B25 (523i E series) or N53B30O0 (the most powerful of these engines: 330i; 530i; 630i E series; 530i F series) – the only solution is to use/enjoy the performance offered by the manufacturer. If your car is equipped with N53B30U0 (325i; 525i E series vehicles or 523i; 528i F series vehicles), it is possible to upgrade this engine to the most powerful (272 .. 280hp) version. Read more here, here, and here.
  4. For N series engines (including N43/N53), the correct engine performance is not possible if the control probes are disconnected (to hide problems with the CO catalytic converters); if all probes are disconnected (“sports” projects); if the NOx system is “deleted” from the software; any type of the “chip tuning” is performed.
  5. If your car has modified software (“deleted” NOx system; “switched off” control or all probes; their error messages are deleted, a car is ”tuned” to ethanol, etc.), the first stage before installing the NOXEM is restoring the stock software. This is a critical requirement. If a damaged (exactly – damaged, not ”tuned”/”modified”) DME software is used, the performance of the engine is incorrect, and the NOXEM can be damaged, too. In this case, any warranty on NOXEM is terminated and refused. 
  6. NOXEM restores the correct performance of the NOx system (and, accordingly – of the whole engine). All types of adaptations (injectors, banks, overall engine adaptations) are restored in all engine performance modes/driving conditions. The correct thermal and chemical conditions of the engine and the exhaust are restored. Unfortunately, NOXEM cannot solve the dripping/leaking of the injectors, “repair” damaged CO catalytic converters, leaking HPFP, etc. NOXEM cannot restore worn-out spark plugs and damaged ignition coils. These defects should be solved in the next repairs.   
  7. Restoring the correct performance of all engine systems (restoring the DME stock software and repairing the NOx system), DME resumes many previously discontinued service procedures. DME restores the measurement of the CO catalytic converter performance, measuring the injector atomization, leakage, and other parameters, and it is able to identify misfires correctly, etc. Due to this, a situation where, after the initial repair, the error messages, which were not present previously, appear is possible.  These are not new problems, but the problems that have existed for a long time (but previously were hidden/unidentified) but can only now be correctly identified and “presented” to the diagnostics specialist to make the further repair of the vehicle easier.
  8. The NOx system allows/forbids Stratified charge and determines the regeneration/desulfation intervals of the NOx catalytic converter. A performing NOx system (if the Stratified charge is allowed and is used) cannot cause misfires, uneven engine performance, or other abnormalities; switch off LPFP, HPFP, some cylinders, etc.
  9. If you have observed misfires exactly in the Stratified charge mode (after restoring it), pay special attention to the ignition system. For the Stratified charge mode, a more powerful spark is necessary, which means that the condition of the spark plugs and ignition coils should be good. Here and here, you will find information regarding spark plugs, which can be used for the N43/N53 series engines. Here is a summary regarding the ignition coils that can be used. Here – more detailed info regarding rare and specific defects of the injectors, which affects exactly the Stratified charge.
  10. Incorrect fuel mixture (and not performing NOx system is one of the causes of this problem) causes damage to the CO catalytic converters. These catalytic converters are very expensive (EUR 4000 .. 7000). Unfortunately, no alternative products are suitable (CO catalytic converters of the N43/N53 series engines are different from the “regular” ones). This is exactly why we recommend repairing your car’s NOx system immediately! Replace the leaking injectors and solve the misfire problem so you can prolong the life of the CO catalytic converters. CO catalytic converters are critically necessary to pass TI (emission test). Unfortunately, there is no workaround or cheap solution.
  11. If you are using the NOXEM, you can replace the NOx catalytic converter with the resonator. Although we don’t recommend this “upgrade,” – it is not necessary. Read more here.
  12. If the exhaust of your car is modified, incorrect performance of the engine/DME is possible. For these engines, DME (also) uses the exhaust pipe model simulation tools – to analyze all readings of the exhaust sensors in real-time. DME “sees” all modifications (for the wideband and control probes – changed location; spacers installed; etc.; changed location of the NOx sensor, etc.). If you are using a modified exhaust, we don’t guarantee a correct result. Any modifications of the hardware or software – it is your responsibility! In this case, no claims regarding the performance of NOXEM are accepted.
  13. Leaking injectors, misfires, oil (increased oil consumption), water, water condensate (short, rare driving distances), and mechanical blows are damaging the exhaust sensors. The NOx sensor is located in a very harsh environment: low exhaust temperature, the possibility of the water condensate, and often blows off foreign bodies (pebbles, rocks, blows when hitting the pothole, etc.). More about this read here. Bimmerprofs offers a range of optimal solutions if your NOXEM gets damaged. We offer a DIY repair option. We offer to perform the repair work for you if you ship the damaged sensor to us. We offer the KIT option, which allows you to replace the sensors by yourself quickly and easily. For more about these options, read here and here.
  14. We offer help with the diagnostics. If you or your service specialist has some questions regarding the performance of the engine, we invite you to get in touch with us. 
  15. A must-have tool for the diagnostics of these engines (N43/N53 series): INPA (loader 2.023 for MSD80); ISTA; EML327 with the appropriate software, which “sees” OBD Mode 6. ISTA P or WinKFP tools are necessary for the software upgrade. Make sure that your chosen workshop uses these tools. 
  16. If your diagnostics specialist does not use INPA; ISTA or is not ready to send technical information in case of any questions/problems, we recommend choosing a different workshop. We work with technical data, not guesses. The requirement to send technical data is a standard procedure in all cases when the diagnostics of the engines should be performed or the decision regarding the necessary repairs should be made.
  17. After installing the NOXEM, the obligatory requirement is to perform the service procedures, which are indicated in the User manual of the exact product. These service procedures are the requirements of the vehicle manufacturer BMW AG, and a correct performance of the engine without performing these procedures is not possible. 
  18. Be careful when purchasing expensive spare parts: HPFP, injectors, catalytic converters. There are many counterfeits in the market. Even several large and as if solid companies are selling fakes and “restored” spare parts, which don’t work. In case of questions, get in touch with – we will advise regarding spare part purchases.