Hi everyone,

I've been having this weird problem with my 2015 S63 and despite going to several mechanics no one seems to get what the real problem is.

Whenever the engine is cold or been off for few hours and turned on, the check engine light comes on.
This happens with a soft single knock sound from the engine just before the RPM starts dropping to idle.
If the engine is warm or been driving the car for a while and erased the code, its all clear until the next cold start.

The code reader shows: " P035396 - The ignition coil 3 actuation has an open circuit or other electrical faults. An internal component fault exists."
Changed the spark plugs, cylinder 3 ignition coil, cylinder 3 fuel injector, re-programmed the ECM, changed engine oil and filter (as routine), and still the problem persists.
A mechanic said that I needed to replace the ECM, another claimed he needed to dismount the engine and open it up to have a look!
I have attached the Xentry diagnostics for review.
Also worth mentioning that it has a K40 scanner installed on it by previous owner.

I would appreciate if someone had come across this fault before and knows how to fix it.
Thanks in advance.

Thanks for your reply.
Indeed I have wasted a lot of money but I had no choice as I live in an area with no good workshops around, hence asking for advise.
I have attached the diagnostics file to the original post which all the mechanics seen but ah well...