Hello everyone. I have had an issue with my E61 for a couple of months. After coming back to my 520d after shopping it would crank up but not start, presuming it was a battery issue, I looked in the boot and saw a couple of inches of water in the battery compartment and presumed this was the fault, pulled out the battery and dried the area, unplugged the terminals for 10 minutes and reconnected for it to get me home 80miles away. I had to unplug the battery on a few occasions to get around as the auto electrician scheduled me in for 10 days ahead. In the meantime, the car would not start. took it to the auto electricians who mentioned he was unable to "read it" but said it would need an ECU as that was the fault. He felt the battery compartment water ingress was not the main issue and was a coincidence Unfortunately a new ECU did not correct the issue and the auto electrician. He mentioned the battery needed changing which I did. I have managed to download ISTA+ and get a scan completed, I will list the diagram below. It initially flagged up 27 faults of which 3 will not delete (images below)
I have had issues with the key in the past, where, on occasion it would not go into the slot (transponder type key) so not sure if this is an issue. As you will see from the diagram the DSC and DDE are in red and will not correct using the program. I need some direction in regards to what I need to check on the car. The auto electrician mentioned he had checked all the fuses. Is there a possible misalignment issue? Do these vehicles have some sort of anti-theft mode? The car key works after many presses to open the car. It does not make the sound it usually makes when inserted into the slot. Are there any relays I can check to see if they have corroded which is not letting the car start or could it be a starter motor issue? Any advice would be much appreciated. I have emptied the boot and all the electrical equipment in there is completely dry (picture below). I will include as many pictures as possible; Unfortunately, I am not an expert using ISTA+ so will need some direction. Your advice will be much appreciated.
scan results
initial faults part1
initial faults part 2
main issues
boot
in car
