N53. Work of professionals

An owner of the car with N53 approached me. According to him, the car has some problems. The engine is vibrating, tends to shut down at the intersection, or if the throttle is pressed only slightly. There is also a problem with an inlet VANOS. Required and an actual position in the problematic driving conditions differ, replacement of the solenoids and sealing rings does not help.

He sent me also the data of the Testo log:

Yes, indeed – there is a problem. VANOS positions do not match (circled with red). But before starting to deal with VANOS, I asked to send me the primary data of the diagnostics.


Here, already the first strange things:

In the history list: in total 4 .. 5 different error messages, which DME “does not recognize.” Even so trivial then, for example, the connection of the air mass meter.

My “little” experience says – someone has “upgraded” the DEM software here!
I checked the NOx sensor menu as of next. The NOx system is the most popular “goal” of the modifications.

Here, for a disconnected sensor (2EAE error is active – connection with NOx sensor is lost), the Lambda is 200 (!), also other parameters – completely incorrect! There is no more even the slightest doubt that the software of the DME is damaged. Besides, damaged very incorrectly:

  • the error messages regarding the NOx system continue to appear;
  • DME does not recognize other/not connected error messages anymore;
  • with no apparent reason, several registers acquired completely incorrect values.


Let’s see, what are the consequences of such an “upgrade” of DME.

Fuel mixture: unrecognized registers appeared, incorrect Lambda in the 2-nd bank.

Fuel mixture: incorrect multiplicative LTFT; improper fuel distribution between cylinders, improper trimming of the Lambda probe in the 2-nd bank:

Rough run data: incorrect mechanical efficiency of cylinders:

As we see, the efficiency of cylinders No.3 and No.5 is incorrect, Lambda in the 2-nd bank – still wrong.

Live data of the injectors:

Here, no Delay, no Flowrate corrections are applied to the injectors! How so?

And here is the answer:

Corrections of the injectors in the Homogeneous mode are not even intended! Their correction maps are not yet available anymore!

Let’s see, what happens in Stratified charge mode:

Possibly, the designation “interesting data” would be the most appropriate, but it is clear – leak compensation times and Delay times of the injectors are not measured.

Here, the “performance” of the ”professionals”:

  • all measurements of the injectors paralyzed both in Homogeneous and Stratified charge modes;
  • corrections of injectors – not applied;
  • Lambda probes – are not trimmed (they have been replaced because of the error message regarding Lambda probes has appeared – the replacement didn’t help);
  • Fuel mixture – incorrect;
  • fuel distribution between cylinders – incorrect;
  • performance of other hubs (including VANOS, which is not even able to maintain the target position anymore) is completely paralyzed.

No illusions – the NOx catalytic converter is damaged, with a probability of 99% – the CO catalytic converters also are damaged (due to long-term driving with the incorrect fuel mixture).
Performance of the “chippers” – financial losses in several thousands of EUR and neverending fight with unavoidable problems: vibration, shutting down, significantly increased fuel consumption, at the same time – reduced max torque, etc.

p.s. Judging by the menu of the NOx sensor, such a type of “improvement” is not an individual work (it is not unique – such crippled data I see regularly) – obviously, such an “upgrade” of the SW is included in some file pack or script of the SW for the “chippers.”