wwwFLA

Fob opens and locks doors and hatch but won’t start car, 2011 Grand Sport M6, unless in slot even with new battery. Shows No Fobs detected.
Have not seen this case in the previous searches I made. Any experience with this?
Full Disclosure: Went swimming with this fob. Nothing worked when originally out of ocean.
Took it apart, removed battery and dried all parts overnight. Also used electronic cleaner on battery and other contacts.

lbzraptor

Probably blew something on the printed circuit board. Wife spilt water on the I-drive thing on the console of her BMW and it short circuited the board. Expensive 450 bucks fix on that. lol. Only other thing is I put a new battery in my fob one time and there was a clear plastic covering on one side of the battery that I didn't notice. Took that off and it worked.

owc6

Well, it the fob works to this extent, it works and is still programmed.

Contacts could be corroded from the water, or the new battery is not good. I bought a multipack and 80% of the batteries weren't good enough to use in the car. I put them in other devices and they worked just fine. The cars need fob batteries that are super strong, and if they aren't, then they won't work. Usually anything 3 or less volts is just not good enough.

88redconvert

Does the other fob start the car properly?

FatsWaller

Salt water is an electrolyte. Even if you dried the fob somehow, unless you rinsed it first, there will still be salt remaining on the circuit board and interfering with the electronics. You could try rinsing everything with distilled water a few times, and then dry well. Putting the components in a container of uncooked rice overnight works realty well. The rice will absorb water. Then carefully clean the contact surfaces.

wwwFLA

Thanks for the replies and advice. I’ll try another new battery and measure voltage in this one.
My other fob works just right.

wwwFLA

Just to follow up. Checked battery, voltage was 3 volts. However, now the fob will not start the car when in the slot. Guess the circuit board finally bit dust.

Landru

Salt water's the worst for anything electronic.
Try doing as suggested above, rinse w/ clear water & thoroughly dry.
See if that works.

2 things re fobs.
Make certain batteries are articulated properly avoiding batterie types w/ crosshatch on rear. For some reason those type make poor contact.
Make certain batteries are fresh, Lord knows how long these batteries sit and many have been found to shot outa the box.

billmoore48

New CR2032 battery should be 3.3volts. 3.0volts gave me the same symptoms you're experiencing. Try a Duracell, that worked for me. You might also want to bend the contacts on the FOB circuit board just a little to give more contact pressure - like 1/16", not 1/8".

dpigguy

I have the circuit boards out of 2 new fob I bought. It’s for a 2008 base coupe with remote entry, etc.

Part Number Part Name
25926480 Transmitter
25926479 Transmitter

if those part numbers work on your car, send me a PM. I’ll pay it forward and donate one to yoU if you want.

buckmeister2

You are correct. My multi-pak of fob batts had 5 out of 10 that were dead. Poster needs to buy a new, new battery first.

FAUEE

If it doesn't work in the slot, it's not the battery.

Landru

IIRC there were a few reports the receiver for fob slot could come loose, rendering slot useless.
Worth a check & didn't seem difficult, if only to rule it out.

buckmeister2

In his original post, he stated the vehicle would start with key in slot.

Dano523

To get into the car (hence unlock the doors), only one of the 5 RCDLR's antenna's has to pick up the fob.

To start the car, 2 on the RCDLR antenna's has to pick up the fob, to show that the fob is inside the car. The location of the antenna's are one at the slot, one inside the RCDLR (its above the radio in the dash), one of the 2 that are in the B pillar (think just in front of the gas fill door), and the last is in the back the car.

The exception to the 2 antenna rule to show that the fob is inside the car, is the slot antenna. even with the battery removed from the Fob, that antenna is right next to the slot to pick up the Fob with a very high signal. Fact is, this same slot antenna is also used to program the fobs into the RCDLR.

So since that fob is working to get into the car, only works in the slot to start the car, tells me that may not be a fob problem, but something in the car putting out enough RF noise that is blocking the second antenna from being able to pick up the fob instead. Or, one of the antenna's has a problem isntead.

So with Fob in right pocket, should be the drivers side B pillar that picks up the attenna, and most of the time, either RCDLR or other B side attenna that be picking up the fob as well.

If the problem is an antenna, use a Tech II to go into BCM data, and just walk around the car with the fob while checking fob signal strength. At some point walking around the car if you do have a antenna problem, signal is going to drop out. When this happens, start at the RCDLR to see if the problem is just a corroded connector pin that is causing the problem at the antenna for that location around the car.

If signal strength does not drop on the walk around the car, then its a RF noise problem in the car instead.
Hence figure out what you added/changed in the car that could be causing RF noise. Could be a phone charger, maybe Radar detector, or something even worse, LED bulbs that you swapped out to instead. Hell, could be a new phone that you keep in the same pocket the problem instead.

wwwFLA

UPDATE

So I found a battery that showed like 3.2 volts. Car would now start only in slot again.
Got a new Fob through my extended warranty.
When adding new Fob I also added defective Fob it showed as known Fob.
When I tested both added Fobs, all functions worked including starting car outside of the slot!
Success!

Thanks for all your help and motivators.