Hi guys first time posting here , hoping to get some advice or answers to what could possibly be going on with my car. Some backstory on how it all began, my city had a pretty bad rainstorm to the point where subways were flooded and most highways. Only way for me to get home was to drive through some heavily flooded areas. Day after I noticed that my aftermarket alarm system was acting strange(alarm triggered for no reason) I didn’t think much of it because the car still turned on and ran fine. A week after, I was on my vacation down in Florida where I started getting notifications through the DRONE app of the car alarm going off saying that the trunk and hood were opened, so I reached out to a friend to check on the car because I left it parked back home by his house, he said the alarm was going off but everything was closed. I figured the alarm system just probably went to **** because of when I drove through the water. A week after I got a CEL light pop up and got codes C1109( Battery Voltage Abnormal) & P0462 ( “Fuel Level Sensor ‘A’ ‘Circuit Low). After some digging around I saw many post saying that it’s related to the BCM, but slowly other electrical problems started to occur. My license plate lights started to flicker and eventually went out, most recently my left headlight bulb went out and the car has started to struggle to turn on at times. Once it started to struggle I immediately had someone check the battery and they had told me everything was good and it was charging up fine. I’d much rather not take it to the dealer or a shop where it could end up costing me an arm and leg for them to figure out where the issue is coming from. It all seems to be stemming from one component. My best guess would be that it’s the IPDM since that’s where all the fuses are for the electrical problems I’ve been having, I just don’t see how it could’ve gotten wet because it’s fairly high up on the car. If anyone can point me in the right direction I would greatly appreciate it

 

When you drove through the flood, how high did the water level get? Was it up to the doorhandles? Any intrusion into the cabin?

 

None that I noticed, that’s why I thought everything was fine. Is it possible that it would be a ground connection? The water level of the flood was about half the height of the car

 

While anything is possible, the likelihood that water flooded into the module is slim. Because of where the module is mounted, the water level would have been almost as high as the top of the fender. Unless the car sat in a lake, the odds that splashing water found its way to the IPDM is low. Again, anything is possible. That said...

Did you open the cover to the IPDM and see if there was water inside?
Did you check any of the other electronic boxes under the hood?
Did you pull up the passenger-side carpet and check for water?

 

I haven’t gone into the IPDM yet because I know it’s a PITA to get in there, wanted to hear some suggestions first. I did pull up the carpet when I got back from vacation and it was dry, then again it was a week and a half later, and I only checked the small box that’s in front of the battery. Would it be risky to unplug and replug the BCM at this point with the issues I’m having ?

 

I wouldn't. And you checked under the carpet- not just the floor mat? Driver side as well? Take a paper towel and lightly wipe over each of the BCM connections- dry?

Best advice is go over every wiring connection/ electronic component under the hood as well as both footwells and look for anything out of the ordinary. I know getting access to the IPDM is a nuisance, but at this point you are flying blind playing the "I wonder if" game. Set aside some time, remove the cowl, pull the IPDM, open and check for water.

 

i will try that today during my break at work, yesterday I checked out the BCM and under the carpet and everything looks not a day old brand new, even the ground, no signs of water entering. I then tried to unplug the alarm system to see if that may be causing a short somewhere and nothing. Something I found interesting is that when I unplugged it I got the notification on the app ‘low battery’ when I haven’t been receiving any notifications at all from the app, I believed the alarm system just went bad all together because the car wouldn’t even unlock or lock with the alarm key. Next I went to clean the battery terminals and checked the fusible link to see if that could possibly be the issue and nothing. I’m considering buying a new battery if I see nothing wrong with the IPDM. I also sourced out a spare IPDM from a donor car just in case

 

Check under the battery tray as well. If there is something blocking the "drain" hole below the battery and water is getting in, water could pool up and potentially cause issues as well. Probably not the case, but worth checking and it's quick.

 

Start disconnecting and checking connectors for water. Though some BCMs are resilient to water, not so much if the water was dirty(flood) that once it dries up it leaves dirt residue.