Damaged the only key!!! TIFU...

[ekjdm14]

OK, so today I've royally screwed up. Was replacing the lock button on the key to our '02 330d & from the looks of it I've grazed the long coil with the soldering iron, which presumably was the RF coil for the immobiliser?

Either way, we now have a key where all the buttons work again which is all good, but it doesn't allow the car to crank or start. (have bridged the starter to confirm it's not a coincidental starter failure, engine cranked but obviously no start as it's not recognising the key).

The first question I have is, the fine copper coil on the right side of the key's PCB, is that a tuned part of the RFID system or just an oscillator coil which could be replaced with one from a scrap key?

Second question, assuming the coil is indeed unique to each key, where do we stand as regards getting a new key coded into the car? (Bearing in mind I've just murdered the only key we had, with a slip of the hand!) Are there auto locksmiths with the equipment to add a new key without a working one to begin with, are we at the mercy of the stealer etc.

Thanks in advance, and advice of the day is "If you only have one key for your E46, make sure to get a spare or two made BEFORE you lose or break the original"

[yjsaabman]

BMW made 10 keys programmed to the EWS (immobilizer) when they built the car. Buy a new key from BMW and all you have to do is perform the learn/sync procedure for the keyless entry transmitter portion.

As for programming an aftermarket key to the EWS? Here's a link that explains what you need and how to do it. Guy there said it's cheaper than buying a key from BMW, but my math doesn't show it as enough cost savings to be worth the hassle. Tols from here, parts from there, get the blade cut somewhere else...I'll just order from BMW and stick in the slot and have it work, thank you.

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[ekjdm14]

The 10 keys thing is a myth from what i've read, it's just that the EWS can only hold a maximum of 10 key codes & after that you're struggling. (think about the cost implications of holding, say, 8 spare keys for every car you produce, over 20+ years. There's no sane business in the world that would use that model). Also, local dealer to us wants £350 (that's three hundred and fifty pounds!).

From what I've read elsewhere though, I may actually be able to replace just the coil since there are locksmiths over here who offer chip transplants onto new PCBs so it's looking like the coil itself may just need to "ring" at a specific frequency. Will try and find a scrap key and see what can be done since there's no way I'm spunking over 60% of the purchase price of the car on a new key if it can be helped! Thanks for the response nonetheless, will get back if we manage to sort the thing.

[ekjdm14]

OK, on further research the coil which I damaged is dual-function. Firstly it serves as part of the RFID circuitry on ignition cycle & secondly it acts as an inductor for wireless charging of the fob battery. I shall acquire a used key and be more careful with my soldering iron tip!

[328 Power 04]

The 10 keys thing is a myth from what i've read, it's just that the EWS can only hold a maximum of 10 key codes & after that you're struggling. (think about the cost implications of holding, say, 8 spare keys for every car you produce, over 20+ years. There's no sane business in the world that would use that model). Also, local dealer to us wants £350 (that's three hundred and fifty pounds!).

From what I've read elsewhere though, I may actually be able to replace just the coil since there are locksmiths over here who offer chip transplants onto new PCBs so it's looking like the coil itself may just need to "ring" at a specific frequency. Will try and find a scrap key and see what can be done since there's no way I'm spunking over 60% of the purchase price of the car on a new key if it can be helped! Thanks for the response nonetheless, will get back if we manage to sort the thing.

The 10 keys is not a "myth"... but I guess it depends how you interpret the phrase.
The keys aren't *actually* physically made... they are just assigned to the car. BMW has the key data and can cut you a key specific to your car that will be plug and play, as needed.
No, BMW doesn't have a vault of physical keys, but they do have 10 keys available and reserved for that car, to be made from their blanks.


Now, many other locksmiths can do the same, but they will change your ews key data in the process.

[ekjdm14]

Gotcha, that's a better way of putting it, that the codes are assigned but the hardware is not made until requested.

Anyhoo, hopefully located a key to rob the coil from so will report back when we have it & have made the swap.

[ekjdm14]

Other key arrived yesterday, swapped RF coil and also made use of the much nicer top half of the key. All good again, car fired up happily and I'm out of the doghouse haha