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In BMW gasoline engines sometimes occurs such a phenomenon as "super detonation" (this is the name of the problem in BMW, in technical literature more often called LSPI).
Unfortunately, this error is first recorded in the so-called shadow or secondary error memory (not visible in ISTA) and only then appears explicitly. Often too late, in this machine the piston of the second cylinder split and blew out the spark plug.
       
With eXtratool there is a great opportunity to check if your engine has been over detonated or not.
Also eXtratool will help you to check used cars. All cases of over detonation are recorded by the DME unit and are not deleted during programming. If you find overdetonation in the used cars you should refuse to buy or bargain for the amount of very likely engine repair with replacement of pistons (most often) or replacement of the block if scoring on the cylinder block.
What is the fundamental difference between superdetonation and the usual detonation. At super detonation the cylinder pressure is significantly higher than at detonation and the peak pressure in the cylinder is much closer to TDC than planned. In addition, the light degree of detonation is used by the DME unit to determine the octane number of gasoline and is stored in the memory of the control unit (using the service function you can determine the quality of fuel from the last 5 refuelings). According to the signal from the detonation sensor, DME rolls back the ignition advance angle and detonation stops. Super detonation can be eliminated only by disable the injection; when disable the ignition coils, super detonation continues, because the ignition source is inside the combustion chamber and cannot be controlled by DME.
The normal pressure values inside a BMW gasoline motor never exceed 110 bar peak in-cylinder pressure in the M S63 motor. For other motors the values are lower. In the diesel M50D it is 210 bar. During super detonation, the pressure in a gasoline motor is twice as high as in a diesel on average!
The difference between normal combustion, detonation and superdetonation can be clearly seen in the following picture.
   
First, let's look at what happens at detonation with the pressure value and the CV angle.
   
You can clearly see that the CV angle has not changed and the cylinder pressure has increased slightly. DME control unit makes the ignition advance angle a little later and the problem is gone.
Now let's look at the actual pressures that occur in a BMW 4 cylinder engine when over detonation occurs. Each cylinder were measured using a very accurate AVL pressure sensor.
   
Peak cylinder pressure exceeds 420 bar and over a long period of time the cylinder pressure exceeds 200 bar. It is not surprising that a piston not designed for such a load gets damaged.
The most likely causes of overdetonation are shown below.
   
For anyone interested in a more in-depth understanding of the causes and effects of super detonation, I highly recommend this book:
https://research.brighton.ac.uk/files/31...Thesis.pdf

In eXtratool to check for overdetonation select Engine - Detonation
If the result is as shown in the picture below, you are fine - there was no overdetonation.
   
If overdetonation has occurred, you will see the number of times and various details such as engine load, coolant temperature, speed of travel, lambda value at which the overdetonation occurred.
As an example of the text here is this picture from Tool32
   
If you had over detonation and something is not clear then post in the thread.