More and more I receive requests for help to solve the problems with the engines of their cars after “disprogramming” of the NOx system. Such “disprogramming” is offered by some chip-tuners and also some enthusiasts.


What does it means – “disprogramming” the NOx system?

People, who have learned how to switch on the NCS software, have noticed the column “NOx system”, and – turn it “off”. “Specialists”, who are familiar with more advanced tools, “clean” the error message map of the MSD, to avoid the error messages regarding the NOX system appear at all.


Is the NCS intended to turn off the NOx system? Of course, no. Data of this configuration are intended to be used during the development  and testing the software.

Is the problem solved by deleting the error messages from the error message map? Of course, no. The error messages don’t appear, but the problem is still present. Even more – such masking of the problem only makes the real solution (and finding the true problem) in the future almost impossible.


How does the engine work after such “upgrades”?

If the NOx system is turned off, using NCS (or any other way), the engine doesn’t use nor Stratified charge nor Homogeneous lean modes. The engine continues to work only in Homogenous mode. This, as known, is an emergency mode for the N43/N53 series engines. Self-evident – fuel consumption increases.

If not using the Stratified charge, the engine doesn’t perform many adaptations, many measurements are not done. For example, DME cannot measure the leaking of the injectors in idle, it doesn’t create LTFT. The engine doesn’t even the performance of the engine in idle, the evening of the cylinder performance in medium load also doesn’t work.

DME uses 5 .. 10 % of full functionality.

Earlier or later, due to not created adaptations, the error messages regarding fuel trim, Lambda probe trim, misfires, etc. will appear. At this moment the owner of the car starts to replace the Lambda probes, injectors, HPFP – all without success.

Even the problems, as if not connected to the engine, appears – the automatic gearbox switches with lashes, the idle of the engine changes, when the load of the engine changes (turning on/off electric consumers, AC, turning the wheel), switching on the AC is with a hit, etc.

All problems are identical to those, which appear if the NOx system is damaged.

The situation is even worse as in case of a simple defect of the NOx system. If in the case of the defect of the NOx system it’s only necessary to put it in order, and the engine will restore its performance, then in situation after “performance” of such “specialists” the situation is very pitiful. At first, the stock encoding has to be restored, and it can be a complicated task if the error message map has been “cleaned”, the changes are done with unknown software, etc. Of course, restoring the software costs time and money. And, self-evident, after restoring the software, the NOx system also has to be restored. And usually – a lot of money is wasted, replacing the hubs, which actually are in perfect order.


In no way, the N43/N53 series engine can work without NOx system. “Disconnection” of the NOx system in any way is the shortest way to huge problems in the nearest or further future. Bimmerprofs don’t suggest to use such “upgrade” solution. The same suggestion corresponds to disconnection of EGR, control probes and other modifications.