Key fob problem.

[mm84321]

I have a 2007 BMW 328xi with keyless access, and have been having some difficulty with my key fob, as of late. I did not use my car for about a month while I was away during February, and now it seems that my fob remote works only sporadically. I can't lock or unlock the doors with the remote access buttons, and will have to resort to taking the little key out of the fob itself to manually unlock the front door. Sometimes, after leaving the key in the ignition, it will work, but only temporarily. Is there anything I should be doing, or a battery that I can replace, that will help to preserve the life of my key, or does it sound like it's on it's last leg?

Thanks.

 

[Logan]

Call BMW

 

[Dmax]

If you have the Comfort Access option, which let's you start the car without inserting the key and open the door with the key in your pocket, you can try replacing the battery, which is a simple CR2032 coin type cell behind a removable panel on the back of the key fob.

It sounds like your car may not have the the Comfort Access option. In that case your remote is not supposed to be "user serviceable". It uses a rechargeable battery that gets charged when the fob is in the ignition slot. This explains why your key fob works after it's been charged in the ignition for a while. Assuming you're giving the battery in the fob enough time to charge from the ignition, it may need to be replaced if it can't keep this charge for even a day or two.

If you're handy, you can try Googling for some videos and directions on hacking the key fob apart, replacing the battery and gluing it back together. If not, you may need to go to a dealer. I wouldn't be surprised if the dealer charges you $200-$300 for this.

These cars came with two keys btw.

 

[mm84321]

Originally Posted by Dmax

If you have the Comfort Access option, which let's you start the car without inserting the key and open the door with the key in your pocket, you can try replacing the battery, which is a simple CR2033 coin type cell behind a removable panel on the back of the key fob. It sounds like your car may not have the the Comfort Access option. In that case your remote is not supposed to be "user serviceable". It uses a rechargeable battery that gets charged when the fob is in the ignition slot. This explains why your key fob works after it's been charged in the ignition for a while. Assuming you're giving the battery in the fob enough time to charge from the ignition, it may need to be replaced if it can't keep this charge for even a day or two. If you're handy, you can try Googling for some videos and directions on hacking the key fob apart, replacing the battery and gluing it back together. If not, you may need to go to a dealer. I wouldn't be surprised if the dealer charges you $200-$300 for this. These cars came with two keys btw.
Yes, I have the comfort access feature. I was told by my dealer a while back that the fob replacements are around $400-$500, and that the battery can't be replaced. Unfortunately, my second key is currently lost somewhere in my house. Thanks for the reply.

 

[MikeDT]

Originally Posted by mm84321

I have a 2007 BMW 328xi with keyless access, and have been having some difficulty with my key fob, as of late. I did not use my car for about a month while I was away during February, and now it seems that my fob remote works only sporadically. I can't lock or unlock the doors with the remote access buttons, and will have to resort to taking the little key out of the fob itself to manually unlock the front door. Sometimes, after leaving the key in the ignition, it will work, but only temporarily. Is there anything I should be doing, or a battery that I can replace, that will help to preserve the life of my key, or does it sound like it's on it's last leg?

Thanks.

Yes there is a lithium button-cell inside the fob. As you've been using it for 4 years, most likely the battery is almost dead. You should be able to replace it yourself. I've yet to see a fob which is sealed. Might need to pry or maybe a small screw holding the battery cover closed. Instructions for replacing the fob's battery should be in the owner's manual.

 

[Dmax]

Courtesy of member HighVoltage on e90post. http://www.e90post.com/forums/attach...1&d=1259605588

 

[x26]

Originally Posted by Dmax

If you have the Comfort Access option, which let's you start the car without inserting the key and open the door with the key in your pocket, you can try replacing the battery, which is a simple CR2032 coin type cell behind a removable panel on the back of the key fob.

It sounds like your car may not have the the Comfort Access option. In that case your remote is not supposed to be "user serviceable". It uses a rechargeable battery that gets charged when the fob is in the ignition slot. This explains why your key fob works after it's been charged in the ignition for a while. Assuming you're giving the battery in the fob enough time to charge from the ignition, it may need to be replaced if it can't keep this charge for even a day or two.

If you're handy, you can try Googling for some videos and directions on hacking the key fob apart, replacing the battery and gluing it back together. If not, you may need to go to a dealer. I wouldn't be surprised if the dealer charges you $200-$300 for this.

These cars came with two keys btw.

Exactly Right!

The FOB for a 2007 (all) series I believe) have a non-replaceable Battery in the non-comfort access FOB. Take it to the dealer to get replaced.
Don't feel bad about the price even Honda and other lesser brands are $ 300.00 up.

Either that or just keep using the key untill you can get it replaced.

Best Wishes!

 

[Wolfador]

Originally Posted by MikeDT

I've yet to see a fob which is sealed. Might need to pry or maybe a small screw holding the battery cover closed. Instructions for replacing the fob's battery should be in the owner's manual.

They Key fob's for my e39 are sealed, learned that after popping the spare one open to replace the battery, its soldered to the board. Its supposed to recharge when the key is in the ignition.

 

[RSS]

nvm

 

[Cary Grant]

Of no help here... but I am amazed that the original batteries on my Passat fobs are still working after 10 years.

 

[NorCal]

Put it boat on the boat. Problem solved.

 

[mm84321]

Originally Posted by x26

The FOB for a 2007 (all) series I believe) have a non-replaceable Battery in the non-comfort access FOB.
Yes, but mine is the comfort access FOB. I kept it in the ignition when I took a 2 hour drive the other day, and that still didn't seem to charge it. I believe I need a new key.

 

[zippyh]

Originally Posted by Dmax

If you have the Comfort Access option, which let's you start the car without inserting the key and open the door with the key in your pocket, you can try replacing the battery, which is a simple CR2032 coin type cell behind a removable panel on the back of the key fob.

 

[mm84321]

Originally Posted by zippyh

Thanks for this!

I never knew how to pop the cover off until I saw that illustration. I happened to have a spare battery from a food scale that I used to replace it with. It works again!

I guess I just saved $300.

 

[BlackStoneAuto]

Perfect!