Fob In Washer, Battery Died, Comfort Access Not Working - Comedy of Errors

[thegazelle]

Hey there:

Here's a one that may be perplexing.

I recently bought a 2011 535i xDrive, high kilometers, car is in good shape. Some other major issues were fixed on it and some other residual issues remain (more on that another thread). Car drives fine though. I am in Canada

Car came with one fob with metal key built in. Car has comfort access, so I have just left it in my pocket.

Recently I did my laundry and forgot the fob was in my pocket. By the time I realized, the load was already in a bunch of water - maybe 10 minutes in and I fished the fob out of the bottom of the washer which was full of water. I opened it up and there were a few drops inside but I took out the battery and blow dried it, wiped it up with a cloth and then left it in front of a fan all night. Next morning, put the battery in, put the cover on and tested. Fob works perfectly. All buttons work (lock, unlock, trunk, etc.). Comfort Access works, and so does opening my trunk when the car was locked. That was about a week ago. Went to visit my girlfriend 2-3 hours away and no problems last weekend with the car.

This past Tuesday I was cooking and then went to my car to upload some videos to the hard drive (I had an Android head unit put in 3 weeks ago)...I had car in accessory mode (engine not turned on). I went back inside to get my dinner and then forgot I had left the car in accessory mode until a neighbour rang my doorbell and said my lights were on an flickering. I got to the car and tried to turn it off and all the lights were on on the dash. All sorts of errors - adaptive headlights, ABS sensor, key not ignition, battery discharged, bunch of other stuff. I eventually turned the car off but I then couldn't turn it back on. No doubt, after 2-3 hours the battery drained. No problem - I will call CAA and have them come boost it, which they did. After they left, I drove the car around for about 40 minutes and then went home. When I got home, I turned off the car and then exited and tried the comfort access. Weird - it didn't work. So I used the keyfob to lock the car, which it did work.

Next day I go to the car and try comfort access. Didn't work again - all four handles. I also noticed I couldn't open the trunk when the car is locked, whereas before I could. I thought maybe the car battery not charged enough so I drove it around some more. But what's interesting is when I got into the car, the icon for the key with the line across it came on - like it couldn't find my key. Yet, the car turned on fine. After car turned on, icon went away. Drove around some more and then came back and shut off the car and tried comfort access again. Didn't work again.

Talked with my local mechanic. He suggests changing out the key fob battery with a new one. I did yesterday, and no change. Yet I can still lock and unlock the car and pop the trunk with keyfob buttons. Comfort access not working. And when I get into the car I get the icon saying my key is not detected. Yet I can still start the car.

I thought maybe my battery is weak and that's why my comfort access is disabled. So I took the cover off the trunk and looked at the battery - negative post says 3510, which tells me (I think) that the battery is from 35th week of 2010, which is the original battery. So obviously battery should be replaced. Until then though I am trying to figure out whether the comfort access issue is because of my fob, the car battery or something else. I only have one keyfob so it's not like I could try another but I heard they are very expensive from the dealership. I could buy another battery too but not sure if that is the culprit. It is weird that everything worked fine until the car battery died (because I left it on accessory mode for 2-3 hours).

Any suggestions on what I can check?

[f10_M550i]

if your battery is from 2010 that is exceptional but way past it's life. I would replace it asap. Low battery voltage will cause all sorts of weird electrical anomalies.
you can access the battery voltage from the hidden menu on the dash, it should be 12.5 v, and more than than when the engine is running. A good alternator will charge approx. 13v
not sure about 2011 but at least on mine, when the battery is replaced, the cars computer needs to be told that there's a new battery

also sounds to me you need a new keyfob. it's probably got damaged from being underwater.

[thegazelle]

Just wanted to update - I had the battery replaced today with another BMW one. Part of that was the registration of the battery and it was at that time my mechanic said that comfort access has to be re-enabled using his scanner which he did. So even if my old battery had fully charged, it appears that comfort access is not automatically re-enabled, but requires manual intervention.

The message of my car not recognizing the key fob when starting the car is still there though the car still starts without incident. Not sure whether I should just leave this or put the money down for a new fob, which is pricy...

[thegazelle]

Looks like the car key fob not being recognized message has permanently gone away after a day or so with the new battery.