2000 528i Key FOB Question

[Iamthebull]

So my dad's 528i keyless entry doesn't work. Have tried replacing the battery in the key fob (3-button OEM unit) in which a local car audio place did the job. After trying to resync the key, still nothing. The shop used some sort of adhesive to seal the key up, I'm working on getting it opened up, just to see how the battery was installed. Overall the key looks awful now, so I want to replace the key. The key does still start the car, and opens the doors and unlocks the trunk manually.

What are my options? Can I swap the guts of the key and put it in a new shell? Thanks folks.

Can I get a blank such as found here?: https://www.ebay.com/itm/28331485424...Display%3A2.8L

[seagreen323i]

Have you tried checking fuse 53 in the trunk? That was my issue for remote locks.

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[Iamthebull]

Have you tried checking fuse 53 in the trunk? That was my issue for remote locks.

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I forgot to mention that, yes I checked fuse 53 in the trunk and it looked good. I swapped it out with a brand new one just in case and same issue.

I forgot to mention that my local auto parts store has an RF detector for key FOB's. Mine works great with it, my dad's key it doesn't pick up the signal. So I'm guessing battery, or something else. Possible the PCB can fail?

[seagreen323i]

I forgot to mention that, yes I checked fuse 53 in the trunk and it looked good. I swapped it out with a brand new one just in case and same issue.

I forgot to mention that my local auto parts store has an RF detector for key FOB's. Mine works great with it, my dad's key it doesn't pick up the signal. So I'm guessing battery, or something else. Possible the PCB can fail?

Old electronics, anything can happen. Technically you can take the immobilizer chip and transplant it into one of those key blanks then find somebody to cut the key. It's a major pita, just get a new one through somewhere online. There was recently a thread on the best place to buy one.

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[Iamthebull]

Update: I was able to get the key opened up after butchering it with a Dremel. As you can see, the car audio shop used a ton of adhesive. I'm going to check the voltage later, I'm slowly trying to get the circuit board out to check the backside. From a visual inspection, do you all see anything glaringly obvious to cause this issue? Thanks folks.

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[Iamthebull]

Next update: Checked voltage of the key battery, and it's at 2.47V. So that should be within spec. No idea at this point of what to try next.

[BostonJon]

you acknowledged in an earlier post that the key wasnt transmitting a signal when you tested it. if the battery is good than i'm guessing you have an issue with the transmitter. even if the key wasnt properly synced to the car, it should still transmit a signal

[Iamthebull]

you acknowledged in an earlier post that the key wasnt transmitting a signal when you tested it. if the battery is good than i'm guessing you have an issue with the transmitter. even if the key wasnt properly synced to the car, it should still transmit a signal

Yep, and after checking the voltage of the FOB's battery, I would think it should be transmitting. But then, I was able to wiggle out the PCB, and noticed there were two loose pieces beneath. That's never good. It looks like they go to the center button. Pics attached.20230111_175816.jpg20230111_175802.jpg20230111_175749.jpg

[sleuth255]

I was able to swap the circuit of an old key into a new generic blank without issues. However, your problem appears to be related to the circuit board itself. Those parts go to the center button pad and wouldn't themselves create an inoperable condition, but they may be symptoms of a bigger problem. You'd probably need an AK90+ tester to be sure. Assuming that you don't have a second key to test out the car's receiver here. Maybe you could borrow a friend's key (of course all of your friends drive newer E39s lol) and try to pair it with the car to check this.

[Iamthebull]

I was able to swap the circuit of an old key into a new generic blank without issues. However, your problem appears to be related to the circuit board itself. Those parts go to the center button pad and wouldn't themselves create an inoperable condition, but they may be symptoms of a bigger problem. You'd probably need an AK90+ tester to be sure. Assuming that you don't have a second key to test out the car's receiver here. Maybe you could borrow a friend's key (of course all of your friends drive newer E39s lol) and try to pair it with the car to check this.

I actually have a second diamond key for my e39, but not my dad's, is there a guide I can reference to pair my spare key with my dad's e39?

[sleuth255]

Here you go:
1. Unlock central locking system (ZV) using a key that can start the car
2. Get into the car and close all doors
3. Using the key that can start the car, switch the ignition briefly to position1 and then switch off again. The switching time must remain under 5 seconds, otherwise the system is not ready for initialization.
4. Using the key you wish to pair, Press button 2 and hold in (button 2 is the unlock button)
5. With button 2 pressed, press the center button three times (in a space of 10 seconds). Button 2 must remain held in
6. Release button 2.
7. The ZV signals by means of Locking then immediate Unlocking the doors that the transmitter has been successfully initialized.

If you get the signal, try steps 4-6 with the original key within 30 seconds. It may just be that the pairing for your Dad's key is lost. If you don't get an acknowledgment the key is probably bad.
Next test your key. If it works, your Dad's key is definitely bad.

[Qsilver7]

I actually have a second diamond key for my e39, but not my dad's, is there a guide I can reference to pair my spare key with my dad's e39?

Ditto what slueth255 wrote…but do remember that your key can only be initialized to LOCK/UNLOCK your dad’s car. It will NEVER be able to start it unless you change the EWS transponder attached to the circuit board (or the loose transponder in the older type remote key or non-remote keys). PLUS…you must initialize BOTH keys in the same session (see duplicate of slueth255’s instructions below). If you only initialize one remote…the other remote will no longer lock/unlock the car because it will not have the last rolling code assigned by the GM. And your remote key will no longer lock/unlock your e39 although it will still start it. EWS & FZV/DWA are two different features and operate over different RF (radio frequency) signals…and communicate with different control modules.

TIPS:

• KLR = ignition position 1 (not position 2)
• All doors MUST be closed
• All remote keys MUST be initialized during the same session (any not present will no longer lock/unlock the vehicle)
• DO NOT stick the 2nd remote into the ignition…start initialization on STEP 3 just as mentioned in STEP 6

EWS communicates over a 125 KHz RF signal between the key/ring antenna/EWS control module/DME. They share the same encrypted ISN (individual serial number)…and the engine will not start if they all do not share the same ISN.

FZV/DWA (central locking/anti-theft alarm siren system) communicates over a 315 MHz (or 433 MHz in Europe and some other countries) and is under the control of the GM (general module). The signal from the key is picked up by the FZV antenna embedded in the rear window, then travels to the FZV receiver in the C pillars then travels its way to the GM :

[Iamthebull]

So I synced my spare 540i key to my dad's 528i, it was able to lock/unlock my dad's car just fine. Tried resyncing the 528i car and still no luck. Was able to resync my spare with my car and worked fine. To go the extra mile I tried syncing the 528i key to my car, and no luck.

So it would seem the transmitter is definitely bad. Time to repair/replace.

I found this vendor: https://www.bmwgm5.com/Key_Repair.htm who would charge $50 normally, but wants to charge an extra $25 just because the key has already been opened and I had someone replace the battery. Seems kinda...messed up in my opinion.

Do you all recommend any other vendor for key repair?

Thanks again folks.

[sleuth255]

I recommend key replacement actually. Get your Dad a nice new key for his 528i. The one you have is in pretty bad shape with parts falling off.

[Iamthebull]

I recommend key replacement actually. Get your Dad a nice new key for his 528i. The one you have is in pretty bad shape with parts falling off.

I believe that's where I'm at, just trying to keep costs down. Anyone had any luck getting a blank with a new circuit board, off Amazon or ebay, or any other vendor, and use an AK90+ to program the key to my dad's car?