Some of these Ecu’s mounted on the engine use its body and it’s bolts as a ground. I learned that the hardway when I removed it and my mdx wouldn’t start. I had it laying on metal and I heard the little sparking connection noise that you had in the video. I remounted the ecu and the car fired up.
This happened to me when I first got my is250 guy I bought it from said it had a new battery but after I brought the car I couldn't get it to start so I bought another battery and carried all the way back to my car and it didn't fix the problem until a young man made a video about this if you wiggle around the gear shifter it would start the car maybe caused by a transmission wire sensor or parked on a slite incline I was glad to get it to start but mad I wasted $200 for a battery I didn't need but it's okay it's only money down the drain as my dad said to me my entire life
So in your case all you had to do is pay attention to the cluster to see there is no P for park on it. The car needs to know that it's either on P or on N to be able to start.
Good to see you buddy What a coincidence I have to buy the scanner to verify what was wrong with my airbag light on my lexus and find the problem and also my old friend🤣
Message you on Facebook similar issue with my 09 is350 Monday as I was reversing out of the apartment it shut off no crank no start bu battery has full power