A little while ago I encountered a unique situation. Anyhow – first for several years and first of several thousand on the N43/N53 engine, which I have inspected.
Here, the contamination menu of the NOx catalytic converter:
I have to add immediately, that such values you will see only in case the NOXEM is installed.
If the OEM sensor is installed, the calculation of the contamination of the NOx catalytic converter is stopped, if (when):
- the performance of the NOx catalytic converter drops below the allowed level (the error message 30EA is recorded nad the engine stops working in Stratified charge), for a used NOx catalytic converter it happens by contamination of 400 .. 700mg;
- the defects of the NOx sensor appear.
If the car has NOXEM installed, it continues to inform the DME, that the NOx catalytic converter is in a perfect technical condition, not taking into account the real contamination of the catalytic converter. If the desulfation sessions of the NOx catalytic converter are not performed, the contamination of the catalytic converter increases more and more.
Judging by the contamination of the catalytic converter, during the last 15’000km the car was not driving with 100km/h for at least one time! In the technical literature of BMW, such a situation is described as an “incorrect driving profile”.
Nuance, which has to be taken into account: if the contamination of the NOx catalytic converter reaches over the red line (4000mg), the NOx sensor can not be turned in the Online mode:
- as “usually”, it means, executing the basic criteria (warmed-up engine, exhaust temperature above 220oC, driving speed above 20km/h), but – only reaching the conditions, required to start the desulfation session;
- can not be turned on at all, till the desulfation session is started forcibly.
The reason: DME understands, that (not depending on the performance, reported by the NOx sensor), the NOx catalytic converter is significantly contaminated and has to be cleaned ASAP. Accordingly – the error message 30EA is recorded and the Stratified charge is turned off. If the Stratified charge is turned off (and the contamination of the catalytic converter is so high that it even makes no sense to turn on the Stratified charge to detect the actual performance of the NOx catalytic converter), there is no necessity to warm up the probe of the NOx sensor.
What to do in such a situation?
- perform the activation of the desulfation session of the NOx catalytic converter and clean the NOx catalytic converter, driving with speed 110+km/, or:
- register new NOx catalytic converter – clean its contamination data.
After cleaning of the NOx catalytic converter, perform the re-adaptation of the engine.
Note: for now there is no confirmation, that MSD87 acts identical, but – such an action of the DME would be just logical.