E39 square key vs. diamond key

[JNDaddio]

Hey there fellow e39'ers,

I have a quick question regarding the keys to the e39s. Pre-facelift (1997-2000) models had the square key and post-facelift (2001-2003) models have the diamond key. After a quick search my question, which is this, hadn't been answered: if I have a Pre-facelift e39 that came with a square key and I need a replacement, if I were to go to the dealer could I purchase a diamond key and would it work just the same with the car? Or is the Pre-facelift e39 and the diamond key not compatible with each other.

Thanks very much,

Daddio

[Alpina540i]

not compatible

[Qsilver7]

Hey there fellow e39'ers...After a quick search my question...hadn't been answered: if I have a...square key and I need a replacement, if I...go to the dealer could I purchase a diamond key...

Thanks very much,

Daddio

See the first sentence in this reply made on 11/5/11: http://forums.bimmerforums.com/forum...99&postcount=6

[JNDaddio]

Thanks guys. Also now that I think of it, the diamond keys are meant to be charged while in the ignition. Since the older keys don't charge, the older model e39s I'm guessing don't have the capability to charge, so the key would just die and that would be the end of it.

Of course I think of that right after asking the question.

[dareckibmw]

You replace the battery if it dies, that's all. I replaced mine after 7-8 years.

[JNDaddio]

You replace the battery if it dies, that's all. I replaced mine after 7-8 years.

What exactly do you mean? I'm talking about the diamond-key that is sealed and has a rechargeable battery in it. I'm saying that the pre-facelift e39s wouldn't (I'm assuming) charge the diamond key, so you'd in essence have to get a new key every time the battery drained in the diamond key.

[e39hamann]

if you really want a diamond key take a look at this:
http://forums.bimmerforums.com/forum...ht=diamond+key

[JNDaddio]

if you really want a diamond key take a look at this:
http://forums.bimmerforums.com/forum...ht=diamond+key

Thanks for the link. I was just asking a hypothetical question for future reference (possible 1999 purchase). I have a 2001 at the moment so already have a diamond. I definitely wouldn't go through that hassle for a diamond key, just wondering if it was compatible is all. Thanks.

[beemerboy203]

You can get a diamond key! It involves some modding but you don't have to worry about charging it the internals fit with the battery.

[forcemax]

not compatible

wrong!

[JNDaddio]

Also another quick question that I was just thinking about:

Does the diamond key get introduced in the 2000 model year, or with the facelift for the 2001 model year?

I read somewhere somebody selling their 2000 saying "it's a 2000 so it has the updated looking key." Any truth to that?

[e39hamann]

Also another quick question that I was just thinking about:

Does the diamond key get introduced in the 2000 model year, or with the facelift for the 2001 model year?

I read somewhere somebody selling their 2000 saying "it's a 2000 so it has the updated looking key." Any truth to that?

I'm pretty sure it did start with the 2000 model year.

[spdycpu]

Also another quick question that I was just thinking about:

Does the diamond key get introduced in the 2000 model year, or with the facelift for the 2001 model year?

I read somewhere somebody selling their 2000 saying "it's a 2000 so it has the updated looking key." Any truth to that?

I have a 2000 and it has the diamond style key.

[Alpina540i]

wrong!

Umm no.... They are really not that compatible considering the diamond key is setup to use charge through induction technology that square shaped key cars do not have. Also the dealer will not cut you a diamond key for a pre 2000 car.
I have researched doing this and its a pain to do at best with lots of work/money. Hence short answer.

[djkev]

I have a 2000 540it and it has the older style keys...

[Southpaw M]

I have a 2000 528i with a diamond key...

[Qsilver7]

1. This is a simple issue to solve/see/understand...especially when your e39's build date is included in your signature/car info. (oops...there's a lot of forum members that still don't provide that tidbit of info that reveals so much when asking/answering questions ) The new style (diamond shaped key) starts with a 9/99 production date:
   
   Since the 2000 model year starts in June/1999...there are some 2000 model year e39s that will have the old style key...and some will have the new style key...it all depends on its build date. Hope that solves the mystery.
2. The old style & new style keys do share some features in common...and that is that both can be programmed to lock/unlock & arm/disarm any BMW that has the same system & operates on the same radio frequency (315 MHz or 433 MHz). The problem again with the new style keys...is that the key's internal battery needs to be charged for keyless entry & alarm arming to work...so you need to find a way to keep the key's battery charged if your car was built BEFORE 9/99.
   
   Then there's the issue of the EWS transponder & the key's internal battery...the battery & transponder is loose and replaceable/transferrable in the old style key and it is designed to easily be opened with the 2 screws on the rear side of the key...while the EWS transponder & battery, in the new style key, is soldered to the circuit board...plus the key is sealed...requiring a way to crack it open and reseal it if any work needs to be done to the inside of the key...like replacing a dead battery or desoldering the EWS transponder from the circuit board.
3. Here's some info about the new style "diamond shaped" keys:
   
   
   
   

[zM3]

Thanks for the details Qsilver7

The previous owner of my '03 540i drove the car very little (only has 38k miles now!) and one key's remote features don't work. I wasn't sure if the engine had to be running to charge (confirmed key at least needs to be in the Run position), wasn't sure how long it took to get a partial charge (30 minutes enough for 15 remote cycles), and wasn't sure how to confirm (Low Battery message in cluster after 3 uses in a row). Now if I can't get it to work, will try the reinitializing procedure you posted previously - not sure the PO had both keys initialized when the car battery was replaced a few years ago, and it's looking more like that's the issue.

[JJCTHE1]

wow lots of info here! yes I have a late build 2000 and have a diamond key. you guys know your keys!

[forcemax]

Umm no.... They are really not that compatible considering the diamond key is setup to use charge through induction technology that square shaped key cars do not have. Also the dealer will not cut you a diamond key for a pre 2000 car.
I have researched doing this and its a pain to do at best with lots of work/money. Hence short answer.

Wrong again! Been here done it! and who said something about Dealer? All job take around 10 Min and I`ve cut it with Locksmith
http://forums.bimmerforums.com/forum...ht=diamond+key

taping on cell phone

[LaLaRay]

See the first sentence in this reply made on 11/5/11: http://forums.bimmerforums.com/forum...99&postcount=6

[Hwalker1]

I have a 2002 E39 and it came with a working square key with a battery. Unfortunately when I got a new key, the dealership reprogrammed my key by accident while setting up the new key. They forgot to open the car using the remote. Now neither keys work at all. Suggestions please.

[Perern]

My 10/99 528i has the diamond key.

[Qsilver7]

I have a 2002 E39 and it came with a working square key with a battery. Unfortunately when I got a new key, the dealership reprogrammed my key by accident while setting up the new key. They forgot to open the car using the remote. Now neither keys work at all. Suggestions please.

Assuming that you have the 3 button RF (radio frequency) remote key and not the 2 button IR (infrared) remote key...just follow the instructions below and make sure you have BOTH remote keys (or any other remote key you want to have the ability to lock/unlock & arm/disarm the vehicle).

TIPS:

• KL R = ignition position 1 (not OFF, position 2, or engine running)
• make sure ALL doors are UNLOCKED
• make sure ALL doors are CLOSED
• only insert the 1st remote into the ignition
• start 2nd & subsequent remotes on STEP 3 where you start pressing the buttons (as outlined in STEP 6)

[Hwalker1]

I should have said mine is the old two button one that uses infra red and works by sending a beam to the mirror unit.