Nissan's interior modules are cast plastic pieces with tons of copper bars internally along with processors, chips, resistors, diodes, etc.
These boxes have visible gaps and were not meant to take water, let alone dirty, acidic water mixes with conductive degreasers to help clean the iron and other metal dust that sticks to the wheels, car, etc.
When a leak develops and soaks the unit the first thing that needs to happen is power needs to be removed and these modules have to be dried manually ASAP.
The leaving of the the battery, if this liquid is touching other parts of the system will create a chemical reaction. The liquid will either heat up and leave deposits or will start to strip the coating of these bars leaving them in bare copper and will also start the oxidation process.

On does not simply "clean" a BCM. You treat the symptoms by following the diagnosis's.

 

Well, for anyone still following this or interested in any updates or possible resolution...

My car has been in the shop for weeks now. After a lot of headaches and arguing with people higher up in the management team at the dealership, we seemed to have come to a settlement of sorts. Essentially, I had to purchase all new ignition coils, and then they'd help out with the rest. The rest means like labor/bolts/fuses. They told me yesterday they replaced all the coil packs (OEM as they wouldn't use like the Z1 "high energy" coil packs or anything) and the car started up fine... which apparently is a good thing lol... but that I'm still having a misfire in cylinder #3. They said that the #3 coil pack was the "most blistered" most damaged one and now they are trying to replace the ignition coil pack connector (splice/solder in a new one I suspect connected to the wiring harness?).

I was granted a loaner vehicle so at least I can have wheels. I am praying they call me today to tell me the car is fixed and up and running finally again with no misfires or other electrical issues....

 

Reading this, i now never want to take my car in to the dealership.

Sorry to hear all this man.

You certainly have a more level head than I.

I would still document everything and bring it to an independent place after to make sure they did repairs correctly and get a second opinion on what happened.

I wonder if they were dumb enough to leave the Sun roof cracked open and sent it through the wash as I’ve seen that one happen(not good)

 

Thanks, man, glad I could help steer a fellow G owner away from the dealer. I knew dealers always had a reputation for charging more than your average mechanic... sometimes I figured it was worth it if it was an issue unique to a make/model... I also used to figure dealer mechanic techs were smarter/better at their jobs than (no offense) the mechanic at your local Do-It-All tire/oil change shop... I thought dealer dudes were more highly trained and held to higher standards for work performance and knowledge, especially for the "higher-end" luxury brand vehicles... That is NOT to say if you're like my ex-GF that justifies you paying the Audi dealer $400 for an oil change I can do in the garage for $50 lol

I'm documenting as much as I possibly can, that's for sure! I wish we had like hidden cameras installed in our cars to catch mechanics/techs or to keep them more honest. JK that sounds kinda Black Mirror-esque. But I digress. I'll certainly look it over myself and take it somewhere else as well. It's possible the sunroof was open, although I don't know why it would have been unless the tech opened it by accident before the car wash lol. I more highly suspect the lack of both the underbody engine splash shield and the passenger front fender plastic liner in addition to possibly that sunroof drain hose that runs down the passenger side front pillar down into the floorboard ECM/BCM area is suspect...

 

In the spirit of trying to troubleshoot, the dealer called today and said my ignition condenser(s) were fine (I thought there was only 1?) but my car is still misfiring on Cylinder 3. They said they ordered a used ECU and will be hopefully plugging that up today to see if it works...

 

There is only one ignition condenser so they are right.
Also from frying an ecu experience I had no spark on cyl 5 which can happen as well.

Good luck.

 

Well here's to hoping they can troubleshoot their way out of this mysterious apparent Cylinder #3 misfire issue that has suddenly shown up.

Outside of ignition components (replaced all coil packs, plugs).... I can only think maybe something is wrong with the fuel system i.e. injector or maybe fuel rails or pump?

I dropped off my second key fob last night since they said they needed both keys to program them to the new ECU they're installing, hoping that fixes the misfire.

 

Just a friendly update to put a bow on this thread: Got my car back from the dealer today! She runs great, all the problems fixed. The dealership Manager and head foreman mechanic both sat down with me and showed me everything. They were very polite, calm, respectful, and professional. They showed me the wiring diagram for the ignition coils etc and where the ground symbols on the diagram were. They explained everything about how the ground faulted and started blowing things, starting with the #3 ignition coil and on from there. The #3 coil pack was bubbling and blistered and the others were on their way there... The dealership went about and beyond what I thought was going to happen. They even put a brand new ECU in after a few failed attempts at locating a used one. They earned my admiration and respect after this whole ordeal. I feel bad that we butted heads initially, but now it's all gravy! I think if I would have dealt with the top dog Manager(s) from the start maybe things would have been different. Alas, there's really not much else to say now except I owe them a huge thank you for everything they did for me. New coil packs, plugs, and an ECU... should be good to go for a while now! #lessonlearned #don'tchangeenginegroundbolts

I owe everyone who chimed in to try and help a thank you as well. In the end, the dealer was right and they had the car in their physical care so probably had the best "eyes/hands-on" diagnosis. I was just so afraid of getting taken to the cleaners for thousands upon thousands after owning the car for less than 1 month. Big thanks to the dealership management and their top shop tech/mechanic for going out of their way to make things right and smooth over a bad service experience. So thank you to everyone!

 

Thanks for the update, I'm glad the issue is resolved and you are happy

 

Im glad there was a resolute to this. Forgive me for sounding ignorant but unless you left a ground loose or anything out the story I still dont believe it.
What we all want is a resolution at the end. But I'm suspect that the carwash exposed a delicate issue but as a former dealer tech the first thing we looked out for was aftermarket installs.
Aftermarket installs could not be diagnosed with tech-line nor consult, you had to be an experienced tech to figure it out.