Partially fried immobilizer - possibly?

[Qmulus]

Got the PM and responded.

From the corrosion I see in those pictures, it is a bit surprising that your car is still starting. I wouldn't count on it doing it for long.

The different colors that you see are the salts of the different metals on the board that have dissolved. The water itself doesn't destroy the board, but water with electricity creates electrolysis. That is why you lose functionality a little at a time, not all at once. So, if you know you got water under the seat, it is important to disconnect the battery (most important!), remove the seat and remove and dry out the immobilizer ASAP. If it is done quickly, it is likely that you will have no damage. If you leave the battery connected, and the immobilizer wet, then you end up with this type of damage. It is important to clean up as much of the damage as possible, but if you send them to me, I prefer to see pictures of the board BEFORE it was cleaned. That shows me where to look for problems. Note that the worst damage is generally under the relays, and there is NO way to get to that damage other than to carefully desolder the relays clean it, repair the damaged traces and replace the relays. Just removing the relays can take a half an hour just to make sure more damage is not done, and relays that are good are not damaged.