Virtual probe. Part 1

This time – an interesting case on Online diagnostics. Complaints of the vehicle owner – increased number of misfires in the exact cylinders, shivering of the engine, smoke from the exhaust pipe, and the fuel’s smell in the exhaust.
The owner of the vehicle was struggling with these problems for several years already. The first time he got in touch with me a year ago. During this time, he has replaced spark plugs, ignition coils, injectors. The spark plugs and ignition coils have been switched by places in different cylinders several times – nothing has helped.
The car owner stubbornly leaned back from the Online diagnostics, trying to solve the problems by himself. When his patience (I should say – impressive) was done (or the desire to drive normally finally “beaten” pride), he finally sent the data for the diagnostics.

Here, the error messages in the DME memory:

The error message regarding the check of the control probe of the 2-nd bank. As we see, the probe’s voltage is 0.00V, not taking into account that DME has especially enriched the fuel mixture (in such a situation, the voltage of the probe should reach 0.80V). Furthermore, exactly 0.00V (not, for example, 0.10V or 0.15V). It looks like the signal short circuit on GND.

Here, DME was not able to trim the wideband probe of the 2-nd bank. Reason – voltage of the control probe, not taking into account the enriched fuel mixture, has been 0.00V.
Status of both error messages: active. In addition, in the first error message’s attributes, you can see that the 2-nd bank was switched in Mode 3, which means: open loop. DME is not checking the Lambda probe readings but is using only data of the management maps. Complete crash.
Let’s see live data.

Yes, truly – the voltage of the control probe is exactly 0.00V.

And yes – the internal resistance of the probe is 0 Ohm. A short circuit is possible.
It looks that there is a problem with a probe or its connection. There is only one nuance: this vehicle is equipped with an N43 series engine!
The N43 series engine DOES NOT HAVE two control probes! It has only one control probe, which “response” as a probe of the Bank 1.
Obviously, somebody has “upgraded” the configuration of the DME software!
Why would that be done?

The most plausible scenarios:
a. the car has had problems with the NOx system for a longer time, as a result – incorrect fuel mixture, overloaded CO catalytic converters, the error messages regarding them;

b. “chippers” decided to avoid the error messages regarding CO catalytic converters, simply turning off the control probes. This attempt has happened very “successfully”;

c. ”increasing of power”. Some ”chippers” are ”upgrading” X16i or X18i to X20i to increase the max torque (at least – they think this will help).


Of course, the data processing of the non-existent probe can give certain problems. Of course, it will not succeed in trimming the wideband probe according to the non-existent control probe data that will not succeed. It goes without saying that the engine, working on Open-loop mode, will not perform correctly. The fuel mixture will be far away from the optimal, not even talking about more advanced functions (measurements of the injectors and creating the adaptations).
This is an excellent example, how serious problems could be caused simply by pressing several buttons on the computer! The car owner has spent several thousand EUR to repair the engine and has fought several years! Also – everything has just started. I hope that the vehicle owner will manage to find someone in his near vicinity who will be able to restore the stock software. The “resuscitation” of the car will start with that. CO catalytic converters are destroyed without any illusions, driving for a long time with an incorrect fuel mixture. The owner of the car will have to spend more than EUR 1000 to replace them.