Is there a "transponder" underneath the copper wire in the diamond key inductive coil

If someone has an old "diamond" key, can they kindly cut it open and remove the inductive coil and then unwrap the copper wires so that we can tell, for sure, whether there is a "transponder" (an easter egg, of sorts) UNDERNEATH all that copper wire (or not)?

The reason I ask is this square2diamond key retrofit says there is a transponder underneath all that copper wire:
- DIY - easy way to make a brand new diamond key work in your older car (96-00)

And, this diamond key makeover DIY intimates the same thing:
- Diamond Shape Key Makeover

But, both DIYs would be much easier if one did not have to remove that inductive coil.

Next person who has an old useless diamond key, can you unwrap the coil for us and tell us what you find?

Definitely is not in there, I'm pretty sure it is the antenna.
I did unwrap this thing, one end of the wire is soldered to one of the metallic grips, after that I got two black parts, one plastic and one ferrite.

Thanks you lukas22rojas for posting a pic of that coil UNWRAPPED. As I've stated in previous posts...some of the DIYs for the new style key have ERRONEOUSLY referred to the copper (charging) coil as the transponder...and I've even posted a PIC that actually shows where the transponder is located on the new style (diamond shaped) key. It is the small square chip (soldered to the circuit board) next to the copper coil.

To whomever took the pic below...I apologize for amending it without your permission...but the (EWS) transponder chip is identified for those who may be confused by previous DIYs that incorrectly identify the copper charging coil as the transponder. The coil receives a signal from the Ring Antenna which charges the battery inside the key.

And here's BMW technical info that explains how the NEW STYLE KEY (diamond shape) has a rechargeable battery that is kept charged though induction by a signal sent from the Ring Antenna to the copper charging coil on the key's circuit board.

thanks for the info!! big help.

Originally Posted by QSilver7

some of the DIYs for the new style key have ERRONEOUSLY referred to the copper (charging) coil as the transponder...

IIRC, these two threads, by way of example, say that (erroneously):
- DIY - easy way to make a brand new diamond key work in your older car (96-00)
- Diamond Shape Key Makeover

So that we don't lead others astray, I cross referenced both those threads to this thread just now.

Originally Posted by QSilver7

posted a PIC that actually shows where the transponder is located on the new style (diamond shaped) key. It is the small square chip (soldered to the circuit board) next to the copper coil.

Very interesting. So 'this' is the transponder in the original pic in the OP above?

BTW, I had forgotten about this plea for value added - so I thank both lukas22rojas & QSilver7 for their valuable additions for the tribal knowledge of the team as a whole.

To ensure this information is re-used efficiently, I modified the bestlinks reference for the diamond shaped key to the following:

- The truth about the BMW diamond key transponder (1) and proper initializing (1) (2), opening, charging, recoding, & battery replacement (1) of the new-style diamond key (1) (2) (3) (4) (5) (6) & converting the old-style 1996-2000 "square" key to a diamond key (1) & how to replace the rubber key pads in the old style keys (1) (2)

There is useful information about the fact that even the plastic (valet/service) key has a transponder chip in it over here:
- E39 (1997 - 2003) > Is 5 series so secured?

If anyone has a picture of this plastic-key transponder, it would be interesting to see.

Hi there, I need some urgent help from you guys.
Can someone with high resolution photo of the key, or can open the key to read the marking on a component which is marked in red arrow in my attached picture.
I accidentally damage it while opening the key for battery replacement and apparently the remote function stops working.
Really appreciate it!
Thank you!

Originally Posted by michaelvn

read the marking on a component which is marked in red arrow in my attached picture

I just saw this (researching something else); but all you had to do was go to the bestlinks to find lots of information (mostly from QSilver7) on the transponder informaiton you seek.

For example:
- Diamond key functions (1) & the truth about the BMW diamond key transponder (1) and proper initializing (1) (2) and the truth about the 10-key limit to programming your own keys at home (1) & opening, charging, recoding, & battery replacement (1) of the new-style diamond key (1) (2) (3) (4) (5) (6) & converting the old-style 1996-2000 "square" key to a diamond key (1) & how to replace the rubber key pads in the old style keys (1) (2) & what to do if your key is locked inside your car (1) & a description of the various types of BMW "Remote", "Illuminated", "Spare/Wallet", & "Valet/Service" keys (1) (2).


BTW, QSilver7 posted a nice remote-key function summary here today:
- E39 (1997 - 2003) > 2002 BMW 525i E39 Key Issue

Originally Posted by QSilver7

the remote has THREE features incorporated into them:

• EWS - immobilizing drive-away-protection which shuts down ignition/injection/starter...this system is self powered and does not need the battery inside the key...nor can it be programmed to work on another car.
• DWA - alarm anti-theft siren system...this feature can be programmed to other BMWs that use the same 315 MHz frequency and requires a working battery inside the key.
• FZV - keyless entry system...this feature can be programmed to other BMWs that use the same 315 MHz frequency and requires a working battery inside the key.

Here's his shot in that post of the transponder chip in the old-style key:

Hi all, I'm a new member (I'm from Belarus), but have been driving BMW for the last 5 years.
From first time as I bought my car (on iaai.com) remote function won't works. In an attempt to find why my key won't work properly I opened a key and found what one of the components on mainboard is damaged (chopped).
I tried to make images but my phone hasn't high resolution camera. I used image shared by michaelvn to show where mounted chopped component (thanks michaelvn for this image).
Chopped component marked by green arrow.

By my opinion as an amateur electronic technician, the required component are resistor.
I don't know nothing about value of it. Maybe value writen on it (tiny numbers). Maybe someone can test value by multimeter.

Originally Posted by michaelvn

Hi there, I need some urgent help from you guys.
Can someone with high resolution photo of the key, or can open the key to read the marking on a component which is marked in red arrow in my attached picture...

As soon as I find my camera I will make image that you needed. Now I only can describe this component. I guess that it's ceramic capacitor 1.6x0.8x0.8mm (LxWxH) white color. SMD size 0603. Has grey square on top of it 0.6x0.6mm. By marked side connected to 'C' pin on NPN Silicon RF Transistor (SIEMENS)

Hope that my post will be useful for someone and hope to help from you guys and sorry for my bad english.

Hi, I am a newbie here and to DIY; even though I have read that you can program the remote but when I asked the seller on eBay for the blanks, he told me that I have to bring it to the dealer for programming. So I am confused, is it because the transponder needs to be and can only be programmed at the dealer, or am I missing something here? Please help. Thanks.

Originally Posted by titan0508

Hi, I am a newbie here and to DIY; even though I have read that you can program the remote but when I asked the seller on eBay for the blanks, he told me that I have to bring it to the dealer for programming. So I am confused, is it because the transponder needs to be and can only be programmed at the dealer, or am I missing something here? Please help. Thanks.

Here's the information again:

The remote key has 3 different features that work in conjunction...but are separate features:

• EWS - immobilizing system which uses a programmed transponder in the key that is UNIQUE to your car's VIN and does NOT require any power from the key's battery...it is self powering thru induction using the Ring Antenna around the ignition and the coil that can be seen in the pics above
• FZV - is the keyless entry feature which operates the central locking sytem to lock/unlock the car using the 315MHz radio frequency (in the USA) that is transmitted to the receiver in the car. It requires the battery inside the key and can be programmed to other BMWs that use the same system.
• DWA - is the anti-theft alarm siren system that uses the same 315 MHz radio frequency and arms/disarms the multiple sensors around the car. It uses the battery inside the key and can be programmed to other BMWs that use the same system

BMW dealerships do NOT cut keys...they order them from BMW NA which ships the key already CUT based on your car's VIN...as well as the EWS transponder which will already have the unique ISN (individual serial number) burned to it so that it will start your car. The FZv/DWA features need to be programmed when the car & key are together. But you can do this yourself by following the instructions that get posted just about once a week. (see them posted again, below)

If you buy a new style key "case" off of eBay and your original key is the same type...once you find a local KEYSMITH that can cut the blank...all you need to do is swap the innards of your original key over into the key case you've purchased off of eBay. Make sure you purchase the CORRECT type of key blade....there are multiple types and you have to have the CORRECT kind.

Once you have swapped the guts of your key into the new key case that has now been cut by your local KEYSMITH that allows you to manually lock/unlock the car and start it...follow the instructions below to program the FZV/DWA features to operate the remote features:

Hi, thanks for the speedy response. The eBay seller was selling a blank with brand new chips in them, so it's a brand new chip and transponder. Links below:
http://www.ebay.com/itm/BMW-BRAND-NE...#ht_2088wt_764
http://www.ebay.com/itm/BMW-REMOTE-H...item2a133d79c8

If I am reading this right, the dealer is the only ones that can program the immobilization transponder to my VIN right?

Right...but not even the "dealer" has the ability to assign your car's ISN (individual serial number) to the EEPROM (transponder) inside your key that allows it to start your car. That is done by BMW NA (here in the State), then the key is shipped to the dealer to sell to you with the EWS transponder already coded to your car.


This eBay seller is doing double speak. They apparently know that the EWS transponder has a unique code...and even mentions that BMW needs to do it...but then flip-flops and says that a keysmith can cut and program the transponder. HUH? Where is a local keysmith going to get the ISN code that is specific to your BMW versus the thousands that BMW sells? BMW doesn't even give this information to the local BMW dealership...so how is a regular Joe Schmo from anywhere USA going to be able to get this info? And I just provided you the info on how to program the key to lock/unlock & arm/disarm the car above.

4.YOU CAN GET THE REMOTE PROGRAMMED BY FOLLOWING INSTRUCTION I PROVIDE WITH KEY,NO TOOL NEEDED.YOU CAN GET REMOTE PROGRAMMED WITHIN 1 MIN,[B]THEN YOU NEED TO GET THE KEY CUT AND TRANSPONDER PROGRAMMED BY LOCKSMITH[/B](DEALER WON'T GET THE KEY CUT AND PROGRAMMED,THEY ORDER KEY FROM GERMANY BY YOUR VIN# AND CHARGE YOU OVER $350!!)

Also...remember what I wrote about multiple types of keyblades? The links you provided are for TWO different types of keyblades. One of them is UNLIKE your key and wouldn't work even if you did get the blade cut and the chip programmed.

Thanks, you have been most helpful. I just bought the X5 and the previous owner only has one key left. The two local dealers quoted 198 and 225 respectively for a key. So thinking I could save myself some money, I did some research and almost bought the key. BTW, both eBay sellers sells both types of keys, though it doesn't matter any more as it seems like I need to go to the dealer tomorrow.

Originally Posted by titan0508

...The two local dealers quoted 198 and 225 respectively for a key.....

Unless you actually need another remote key...you could always go with one of the other 4 types of keys if all you really need is a spare/back-up/emergency key.

See if your local BMW dealership will match the prices of one of the other nationally advertising BMW dealerships like BMW SILVER SPRING or TOMKINSON BMW.

Below, you can see the prices from BMW SILVER SPRING's website ( http://getbmwparts.com/ ) ...the list below was gathered this past summer...I haven't gone back to check if prices have changed. Another competitive BMW dealership is Tomkinson ( http://www.bmwpartscenter.net/partlo...?siteid=215996 )...you can check their prices (using the BMW part nbrs from the list below) to see what they are selling the keys for. Perhaps your local dealerships will match pricing (if you print out a page with the price list).

Again, there are other keys that cost much less money if you don't require keyless entry:

What a wealth of info! Just what I was looking for!
Few questions tho, and wondering if this has been done.

If a valet key is bought? does this actually start and run the car for an unlimited amount of time? The reason I ask is because I read that the valet key is only "supposed" to run the car for 10minutes and shut it off, basically just enough for the guy to park it.

What I was thinking of doing, my keyfob is toast.. I can't seem to start my car with it but I can unlock/lock it using the buttons. It appears the transponder is gone in it.

What if a valet key (or the cheapest option from dealer) is purchased and if the transponder if there is any inside of it is taken and put into a master fob shell.

Should that not yield a fully working master key?

What I am trying to avoid is paying the dealer $200+ for the master key.. I have 2 master keys but one does not work it will not start the car.. but all other functions work.

To jeepo23: I don't know where did you read about valet key, but I drive with it for hours.
Remote and transponder are two separate functions within a bmw key fob, they share some circuitry btw.
There's no cheap way to make a new key that can start your car. Only 2 options:
1. Go to BMW and get it, it's of course more expensive but risk free.
2. Go to a locksmith that has equipment and know how to do it. He will need to take out your ECU (EWS), dump the EPROM content into an external device and retrieve a code that need to be written into the new transponder. This step involves the risk of having a copy of your car "secret" with the locksmith, and he can make more keys that potentially can steal your car. There's one more step is to program the car to accept the new key, but this can be done easily and quickly with a laptop hooked up to the diagnostic port.
There's no other way, so down here in Australia where new key from bmw cost close to AUD700, I always advise friends to get a non-remote key at 1/3 the price then transplant it into an eBay fob. The cost is about the same to getting a locksmith to do the eBay key, but it's risk free.
But frankly, who care about theft? BMW cars are usually insured more than actual resell value so if it's get stolen, it's a win

Originally Posted by michaelvn

To jeepo23: I don't know where did you read about valet key, but I drive with it for hours.
Remote and transponder are two separate functions within a bmw key fob, they share some circuitry btw.
There's no cheap way to make a new key that can start your car. Only 2 options:
1. Go to BMW and get it, it's of course more expensive but risk free.
2. Go to a locksmith that has equipment and know how to do it. He will need to take out your ECU (EWS), dump the EPROM content into an external device and retrieve a code that need to be written into the new transponder. This step involves the risk of having a copy of your car "secret" with the locksmith, and he can make more keys that potentially can steal your car. There's one more step is to program the car to accept the new key, but this can be done easily and quickly with a laptop hooked up to the diagnostic port.
There's no other way, so down here in Australia where new key from bmw cost close to AUD700, I always advise friends to get a non-remote key at 1/3 the price then transplant it into an eBay fob. The cost is about the same to getting a locksmith to do the eBay key, but it's risk free.
But frankly, who care about theft? BMW cars are usually insured more than actual resell value so if it's get stolen, it's a win

Sorry bud but I am not following your second option one bit. I've never heard of a locksmith being able to dump ECU's and EEPROMS etc.. I think over complicating matters to be honest.

Basically if a valet key is bought, it starts the car so that means it has a transponder in it. In my situation I cannot start my car with my master fob as the transponder appears to be dead. So taking the transponder from this valet key and putting it in the master fob should resolve this issue and have a working key for a factor of the cast.

But since I am in Canada and only one that can provide keys is the dealer the valet key alone is $100.. Seems a bit steep. I wish I was in america since for USA based ViN vehicles you can get a master fob for ~$120. While the dealer from me wants like $200+..

Also the fob is 2 separate circuits. One circuit is used for remote unlock/lock functions while the other circuit is used for the EWS authentication and starting of vehicle. The two circuits have nothing to do with each other.. That is why you can get a ebay key and program the unlock/lock functions right out of the box without having any other programing/diagnostics/laptops. Also the battery has nothing to do with the transponder on the chip, the battery is strictly used for unlock/lock functions.

Hey if it's only $200 then get the master key from BMW.
I'm not trying to argue or convince you of anything, just that I've spent close to 6 months researching exhaustively for alternative solutions.
The EPROM dump is what I read from the user manual of those programmer that locksmiths use, and also correspond with my knowledge of the ELMOS chip that does the transponder business in the key.
And the circuitry that shares between remote and transponder is the coil. You remove the coil, the battery won't charge and the transponder won't work.
You take out the transponder chip, the fob won't charge as well.

Originally Posted by michaelvn

Hey if it's only $200 then get the master key from BMW.
I'm not trying to argue or convince you of anything, just that I've spent close to 6 months researching exhaustively for alternative solutions.
The EPROM dump is what I read from the user manual of those programmer that locksmiths use, and also correspond with my knowledge of the ELMOS chip that does the transponder business in the key.
And the circuitry that shares between remote and transponder is the coil. You remove the coil, the battery won't charge and the transponder won't work.
You take out the transponder chip, the fob won't charge as well.

So the transponder is the 8pin IC chip then?

For the record, through the process of 'incrementalism', the bestlinks on the key (filled to the brim with QSilver's wisdom) ... is currently ...

- How to replace the old-style BMW E39 square key battery (1) (2) (3) & how to replace the rubber key pads in the old style square keys (1) (2) & opening, charging, recoding, & battery replacement (1) of the new-style diamond key (1) (2) (3) (4) (5) (6) & how to recharge off your BMW and how long a BMW key will last in the drawer before it needs that off-the-car recharging (1) & converting the old-style square key to the newer diamond shaped key (1) & the details on swapping the BMW diamond key transponder (1) & proper diamond key initializing (1) (2) & what to do if your key is locked inside your bimmer (1) & a description of the various types of BMW Remote, Illuminated, Spare/Wallet, & Valet/Service keys (1) (2) & a list of diamond key EWS, FZV, & DWA functions (1) (2) & all about the 10-key limit to programming your own keys at home (1) & a description of the ignition key ISN (individual serial number) ten-second rule (1) & what to do if you lost your only diamond key (1) or what to do if your BMW key was stolen (1)

Originally Posted by jeepo23

...But since I am in Canada ...

Being in Canada may be a good thing for you. There is an aftermarket vendor (RPM Motorsort) that can read & rewrite the EWS ISN (individual serial number) that may work for your situation.

Do a google search for "RPM Motorsport Canada" to find a link to their website. You may want to call them (toll free) for specifics as to your particular situation and the solution they can provide.

As far as the valet key...the transponder in it will be similar to the transponder in the old style key. The transponder in your new style key is the type that is soldered to the IC board. I'm not sure why it is not working (was your keys dropped recently?)...but another concocted key smash up would be finding a blank key shell (like on eBay), and a local KEY SMITH that can cut the blade for you, then cracking open you non working remote and swap the innards over into the new key case PLUS cracking open the new valet key to remove the EWS transponder chip...swap that into your new eBay key case (that you had cut by a local key smith)...the VOILA!...you'll have a new key that can start your car as well as program to lock/unlock & arm/disarm your car.

BTW...the "cut" of the valet key blade is what LIMITS its ability to unlock the trunk & the glovebox...there's nothing "electronic" about its limited ability. If it was electronically controlled...I doubt that the valet key would be one of the cheaper...cost wise. The owners manual ALSO explains the usage for the valet key...see the explanation for key #3:

In the illustration below...you can see where the EWS transponder is located inside the keys (again, the new style key's transponder is soldered to the IC board):

Good luck.

To jeepo23: Yes it's ELMOS 10030A. This chip usually last forever so if you've some electronic skills, try to check the coil and circuit that hook up to it.
If you're lucky, it could be a case of the coil break or circuit break that doesn't allow the chip to power up and read signals from the car.

Originally Posted by QSilver7

Being in Canada may be a good thing for you. There is an aftermarket vendor (RPM Motorsort) that can read & rewrite the EWS ISN (individual serial number) that may work for your situation.

Do a google search for "RPM Motorsport Canada" to find a link to their website. You may want to call them (toll free) for specifics as to your particular situation and the solution they can provide.

As far as the valet key...the transponder in it will be similar to the transponder in the old style key. The transponder in your new style key is the type that is soldered to the IC board. I'm not sure why it is not working (was your keys dropped recently?)...but another concocted key smash up would be finding a blank key shell (like on eBay), and a local KEY SMITH that can cut the blade for you, then cracking open you non working remote and swap the innards over into the new key case PLUS cracking open the new valet key to remove the EWS transponder chip...swap that into your new eBay key case (that you had cut by a local key smith)...the VOILA!...you'll have a new key that can start your car as well as program to lock/unlock & arm/disarm your car.


Good luck.

Thanks for the info! I will certainly have to give these guys a call and see. But Ill quote below how my 2 master keys are behaving. Also I am not sure why the key is not working.. I got the car about a month ago and the PO just said "it didn't work".

This is exactly what I thought about doing! But the dealer here wants $100 for the valet key.. Its a total rip off! So I really do not know if its worth the entire hassle of getting the lock smith to cut it, then find the ebay shell and order a valet key and then do the swap. Again the american prices state a valet key was like $35-$50 and it's totally worth it in that case. Also what scares me a bit is the transponder being that small 8pin chip not sure if my soldering skills would be up to par with that.

Here is my key situation to give you guys a better idea.

We will call it Key A and Key B. Now I will start of as they were last sunday before I started any programming/initializations and gut swapping.

Both Key A and Key B can lock/unlock the car if the key is in the door, the old fashioned way basically.

Key A: Can remotely unlock/lock the car, once the key is put in the ignition after passing all the on/accessories positions it just stops and will not do the last crank in order to start the engine.

Key B: Does not remotely unlock/lock the car but once the key is in ignition will start the car without any issues.

So what I figured, must be a issue in the cut of the key (the one that won't start the car). So I opened up the key to swap the guts out and be done with it.

Swap the guts, bring both keys to the car (carefully noted which one was the key that actually used to start the car) program the keys same was at the video above shows. Same issue as before one starts the other doesn't and one remote unlocks/lock while other doesn't...

I thought to myself okay wtf.. I just swapped the guts now the key that used to start will not anymore but it can unlock/lock remotely.

While the guy that wasn't able to start is now able to do it...

So what I did is then I just took the guts swapped them back without any programming.

And I am back to the same thing as before, the key with the guts that will remotely unlock/lock will not start the car.

But the key that can't do remote unlocking/lock will start the car.

I guess there is something in the chip that talks to the car, I am assuming the chip that actually works with remotely unlocking/locking has something defective that talks to the vehicle and prevents the starting?