F series. FAQ

Q1. Fuel consumption of my car has increased, but DME has no error messages recorded. Where could be the problem?

A1. Most probably, there are problems with the NOx system. Unfortunately, DME of F series “hides” many problems, which are connected to the problems of the NOx system and does not record any error messages regarding its performance. So BMW chooses to “solve” mass problems with this system.


Q2. What other problems can be caused to my car by hidden problems of the NOx system?

A2. Typical symptoms in case of problems of the NOx system: increased fuel consumption; the engine loses “sharpness” and responsiveness becomes “clumsy”, idle becomes unstable; vibration when driving is possible, error messages regarding fuel trim, Lambda probes, misfires; the automatic gearbox can become clumsy, shift with jerks.


Q3. Are there any ways to see the “health status” of the NOx system?

A3. Unfortunately, for F series the data regarding NOx system is very limited. ISTA D/+ does not allow to access any information. INPA allows seeing the level of contamination of the NOx catalytic converter, but the information regarding the “health” of the NOx sensor is not available with any tool.


Q4. Can I test the performance of the NOx system, using INPA/ISTA?

Q4. Yes, you can! More information you will find here.


Q5. I have heard, that the NOx catalytic converter of these cars should be cleaned time by time. Such regeneration has to be done while driving with the speed of at least 110km/h for a longer time. Unfortunately in my region, it can not be done. Are there any solutions?

Q5. The only solution in this situation – the installation of NOXEM. If the car has NOXEM installed, you can avoid the cleaning/regeneration sessions of the NOx catalytic converter.


Q6. What are the consequences if the NOx catalytic converter is not cleaned in time?

A6. If the NOx catalytic converter is contaminated, the engine will not use a Stratified charge and it experiences all problems as in case of any other damage of the NOx system. Unfortunately, in this situation, DME does not record any error messages – the problem is completely hidden.


Q7. Does the car warn me in any way, if the contamination of the NOx catalytic converter reached a critical level?

A7. Unfortunately, the car does not give any warning when/if the NOx catalytic converter is contaminated.


Q8. I have suspicions, the reason for the increased fuel consumption could be problems of the NOx system – contaminated NOx catalytic converter. Is there any option to find out, if the NOx catalytic converter is the cause of the problem?

A8. Yes, you can evaluate the contamination of the NOx catalytic converter, using INPA. More info you will find here.


Q9. My car has NOXEM installed. How to clean the NOx catalytic converter without a real desulfation session (driving in high speed)?

A9. The only tool, which can be used for the F series to clean the NOx catalytic converter: INPA. More information you will find here.

Note: this solution is valid only if the NOXEM is installed. If the car has an OEM NOx sensor installed, you have to perform real desulfation sessions of the NOx catalytic converter, driving with increased speed for a longer time.