[RoundelM3]

I've got a 1/2013 335i that started getting an error message about the "remote" key fob battery needing replacement today. I've changed the battery in the key fob, but I continue to get the error in the BC area and on the "check control" in iDrive. I've tried both keys, and both will remotely lock/unlock the car and everything works normally other than the error that won't go away. I even tested the batteries with a voltmeter and they're both good. My car still has its original battery, so could this be a sign that it's starting to fail?

[upsidedownfunnel]

One thing you can try is holding the key up to the area on the steering column with the key diagram when you start your car. Some online searches indicate that can fix this issue.

Also, where did you get the batteries? A lot of batteries on sale on Amazon are old or counterfeit. I just get mine at a drug store now.

[RoundelM3]

Originally Posted by upsidedownfunnel

One thing you can try is holding the key up to the area on the steering column with the key diagram when you start your car. Some online searches indicate that can fix this issue.

Also, where did you get the batteries? A lot of batteries on sale on Amazon are old or counterfeit. I just get mine at a drug store now.

I tried holding the key against the right side of the steering column where it's marked and that did not fix the problem. I did not buy new batteries, as the ones in my two fobs and those in the 2 fobs for my wife's 2016 228i all showed to be good and producing 3 volts. Her car does not get the error from her key fobs, and swapping those batteries into my primary fob didn't resolve the problem. I've also seen some odd fault codes here and there that are making me think it's the car's battery that needs replacing. After 5 1/2 years it's probably overdue. But thanks for the suggestions.

[Billfitz]

The only way to diagnose problems, and in many cases the only way to clear codes, is with a good diagnostic tool, like the Foxwell NT510. It will cost you about what most dealers will charge to register a new battery.

[DrivenByE30]

My F30 is from 2012.

Never have changed the car battery before (I am assuming it is still going strong since I haven't had any message in that regards).

But both of my keyfobs are receiving the same message as you do.
I have changed so the little button batteries soany times already, even went as far as paying for the dealership battery at $14 a piece...
I am still receiving the same message.

Ruling that the button batteries are underspec.

At this point I am thinking that keyfobs are going bad from me dropping them so often....

One key can't open or close the doors/trunk and has a very difficult time starting the car. The dealer reading the keyfobs shows a record that is over 7 month old... Seems that the key hasn't been able to communicate properly with the car for all that time.

The spare that I have been using for the past 2 years can open and close doors but receives the message (keyfobs not detected) and has a 1 in 8 chance of not starting the car...


Do you think it is the car battery being the culprit ?


Seems strange that the keyfobs would fail before the car...

[RoundelM3]

I went to the dealership and had the car battery replaced - needed it, after 5.5 years. Had them check everything and the tech came out and told me that until he changed the battery in the key, the error would not go away. Now, this is in spite of the fact that I pulled a battery from my wife's 228i fob no. 2, which is only 2 years old, and replaced the one in my fob. Same problem. No problem on her car with that battery, so for some reason, it had to be a brand spankin' new one. Brought the car home, and my no. 2 fob gets the error...but instead of changing that battery, I decided to trade for a 2015 Tanzanite blue M3.

[RoundelM3]

Originally Posted by Billfitz

The only way to diagnose problems, and in many cases the only way to clear codes, is with a good diagnostic tool, like the Foxwell NT510. It will cost you about what most dealers will charge to register a new battery.

I used my Carly for BMW and cleared all codes - there were none related to low voltage or other similar issues. I've had a full-feature "pro" license for Carly for a few years now, and it can do diagnostics, coding, battery registration, and several other features. The license and the BT adapter for Android devices cost less than $100.

[Coercion Shaman]

Originally Posted by roundel335

Brought the car home, and my no. 2 fob gets the error...but instead of changing that battery, I decided to trade for a 2015 Tanzanite blue M3.

I wonder if I could use that as an excuse with my wife.

"Ummm, the fob needs a new battery. I'm just going to get an M3 to save the cost of the battery."

[RoundelM3]

Originally Posted by Coercion Shaman

I wonder if I could use that as an excuse with my wife.

"Ummm, the fob needs a new battery. I'm just going to get an M3 to save the cost of the battery."

One other thing: my wife finds the seats in the M3 more comfortable than those of the 335i, plus she says it feels more "solid" and "safer". Who knew?

[John in VA]

My wife's 328iX had a drivetrain fault/yellow CEL that required a loaner over the weekend. They had her in a new Snapper Rocks Blue 440i - she loved the color & sports seats, but not the long coupe doors. Guess we need to try the Gran Coupe next time!

Generic scanner found P0172 OBD-II Trouble Code: System Too Rich (Bank 1). While the dealer replaced a few parts (Valvetronic motor problem - replaced accuator, eccentric shaft, oil spraying nozzle, needle bearing), it turns out the original battery needed to be replaced, too (10/2012 build). All was well except once home she got the "Replace battery in remote" error, from her usual fob as well as the spare. Seemed odd - they both worked fine last week, before the battery was replaced . Replaced both fob batteries - error message is gone.

[RoundelM3]

Yeah...strange indeed about how just replacing the battery, even though it tests out just fine, seems to do the trick. Even the tech at the dealership was baffled by that one.

[Livetodrive]

The old battery was just worn. Test the new battery - I bet you get 3.2v. or higher.

[RoundelM3]

Originally Posted by Livetodrive

The old battery was just worn. Test the new battery - I bet you get 3.2v. or higher.

The old one tested at 3.4v...that's what was so strange. And since I decided to trade for a Tanzanite blue M3, it's of no consequence any more.

[jeppe777]

Did anyone find a fix?

My main key started doing this. Bought brand new battery same issue.
However if I use the exact same battery in my spare - no error

[Billfitz]

That means the error code is associated with a specific key. Did you read post #4? I can't say if my Foxwell will clear this code, since my car hasn't shown this code. But I do know that most of the time fixing an issue won't clear the code associated wit it, you need to use a tool.

At this point I am thinking that keyfobs are going bad from me dropping them so often....
Seems strange that the keyfobs would fail before the car...

How many times have you dropped the car?

[JoseTheRover]

Originally Posted by DrivenByE30

My F30 is from 2012.

Never have changed the car battery before (I am assuming it is still going strong since I haven't had any message in that regards).

But both of my keyfobs are receiving the same message as you do.
I have changed so the little button batteries soany times already, even went as far as paying for the dealership battery at $14 a piece...
I am still receiving the same message.

Ruling that the button batteries are underspec.

At this point I am thinking that keyfobs are going bad from me dropping them so often....

One key can't open or close the doors/trunk and has a very difficult time starting the car. The dealer reading the keyfobs shows a record that is over 7 month old... Seems that the key hasn't been able to communicate properly with the car for all that time.

The spare that I have been using for the past 2 years can open and close doors but receives the message (keyfobs not detected) and has a 1 in 8 chance of not starting the car...


Do you think it is the car battery being the culprit ?


Seems strange that the keyfobs would fail before the car...

Having the same issue, any resolution?

[bgalakazam]

Same issue, startes thread, no useful replies. Battery has over 3Vdc so it’s good. Spare keyfob doesn’t have issue. Seems to be related to comfort access.

[Kailec]

For those of you having this issue, have you by chance installed aftermarket door projector lights? They are known to cause an issue where your car tells you the fob is missing.

[bgalakazam]

I swapped LED in the front and coded car.

[Billfitz]

Originally Posted by Kailec

For those of you having this issue, have you by chance installed aftermarket door projector lights? They are known to cause an issue where your car tells you the fob is missing.

True, somehow it interferes with the radio transmitter in the door. But it would affect both keys.

[Palantir]

Not sure if accurate but I suspect that since the different brands batteries that fit our remotes have different max discharge rates it affects the way the fobs work/dont work. In my case I replaced the original battery in my primary fob with the same exact Sony from the battery store-no issues. At the same time I replaced the secondary remote battery assuming it might be going bad as well. Again - no issues. My point is that even though the original battery that I replaced tested at 3v when I was getting the message that might not be enough of an idicator for its state. The battery might have not been capable of providing the nevessary "running" voltage under consistent draw. Where the new battery (with adequate maximum discharge rate) was sufficient.
Just my 0.02. It will be great if electronics/electrical professional chimes in.

An internet quote on CR2032 battery usage discharge:
"The consequences of discharging with higher current are that you manage to get less energy than specified from the battery. The current peaks create voltage drops and at the moment when that voltage drop goes below your brown-out voltage - your circuit resets. Needless to say at that point there is still some energy left in the cell."

[Billfitz]

Originally Posted by Palantir

It will be great if electronics/electrical professional chimes in.

It's possible. What you're dealing with is voltage capacity and current capacity. A battery can have what appears to be normal voltage capacity with no load, but when a load is applied the lack of current capacity causes the voltage to drop. You can only confirm this if you measure the battery voltage with a load applied. A meter alone doesn't apply any load.