car key battery

[s.mac]

I thought my car battery was dead but it appears to be the key fob, any ideas how to open the key to change the battery :whistle:

[_Nathan_]

You need a soldering iron...

[bryce]

and a really big hammer...

Good question though.

[dave1]

has the car been stood? if so the battery might just be flat it charges when driving might have just gone out of sync

[Mark CSL]

Use the key they charge when it is in the ignition :thumbs:

Like dave1 said

[s.mac]

Thanks, I will give it a go, I've used the spare for the trip, I didn't know they re charged

[J.D.]

The keys don't have a battery as such you can change. Is a coil which is charged when the key is in the ignition when running.
If you are having trouble opening the doors with the key it could be the GM5 module on the way out. Common problem with E46's. Not sure how affected the coupes are as they have less doors to unlock!! Just had to replace two relays in the module on my E46 Touring.

Good site for info.

http://www.bmwgm5.com/

[Sailorbaz]

Cheers JD, some good info there. So, in theory, if you never use your spare keys, could they loose there charge and result in being defunct?

Is it a good idea to rotate keys then?

[derek]

i thought they had a battery and it was charged via induction maybe im wrong but how does it store a charge for so long as coils don't store electricity, capacitors can

[J.D.]

i thought they had a battery and it was charged via induction maybe im wrong but how does it store a charge for so long as coils don't store electricity, capacitors can

Didn't want to get too technical but yes the key uses a rechargeable battery charged via induction coil. You can replace the battery but involves taking the key apart and having to resolder in a new one once you found the correct type. Is a DIY on it on E46fanatics i think.

Other issues could be that the key has lost its sync with the car and requires re-coding.

I try to remember to rotate the use of the keys to keep them charged but it is possible that the battery can eventually die...

[glendog74]

I see your signature JD - is there a CSL on the way? :thumbs:

[J.D.]

Sure is. One of the faster Black version's. Being prepped at the moment and pick her up once back from Holiday :drool::drool:

[Sailorbaz]

Glendog, was just about to ask the same. :hahaha:

Congrats on your purchase Martin! When you say prep'd, how do you mean? Prep'd for racing/trackdays or just prep'd for delivery to a new owner by the garage?

This will be the one time you'll be wishing your holiday is over quick, you'll be driving the wife nuts I'm sure. :whistle:

[J.D.]

Glendog, was just about to ask the same. :hahaha:

Congrats on your purchase Martin! When you say prep'd, how do you mean? Prep'd for racing/trackdays or just prep'd for delivery to a new owner by the garage?

This will be the one time you'll be wishing your holiday is over quick, you'll be driving the wife nuts I'm sure. :whistle:

A Black 53 plate with 38K on the clock. Having a few bits sorted on the bodywork and a paint correction carried out to get rid of the swirls. Mainly for road use but may try to sneak a Track day in. Trouble is that the wife has learn't from the bike track days the they cost alot more than just the cost of the track day:whistle:

[derek]

good choice Martin enjoy!!