2000 E39 528i alarm issues

[ronnie5]

Hello all,

My E39 has been parked up for a week which beforehand there was no issues. When I went to use the car the key fob button didn't unlock the car so I used the key to maually open it but soon as I open the door the alarm goes off, I can start the car but the alarm still sounds and the hazards flash. I have opened the key which is the diamond shape and tested the battery which is pushing 3.9v so that is ok? I have tried to reprogram the key by getting in car, closing all the doors, turn key in ignition to ignition on, take key out, press and hold unlock button and then press lock button 3 times. I have also tried turning the key to position 1 5 times taking key out and doing the same sequence as before and this doesn't work. I have done these a million times all with the alarm going off. I have checked fuses in boot and glove box, charged the car battery up over night and I'm still getting the same problem. I have a spare diamond shape key but it's doing exactly the same.
I'm stuck on what else to do and I don't want to take it to BMW.
Can anyone solve this problem for me?
Cheers for your time.

[Aubergine]

Have you taken the car for a long drive (hour or so) since it was sitting? I am not sure what the output reading should be from the key battery but that sounds low which would cause the behaviors you are describing. Alternative, setup the key on your electronic toothbrush charger overnight. That often charges them back up.

[ronnie5]

I've been for a short drive today with the red clown nose on the rear view mirror flashing to say the alarm was on. Not enough to charge the battery. These batteries are 3.5v from new so testing them and getting a slightly higher reading should mean they are fully charged. I have a replacement battery on its way in the post but I really don't think the battery is the problem as even without a battery the key in the door should turn the alarm off?
I don't have an electronic toothbrush charger but I do have a mobile phone charging plate if the key charges the same way as wireless charging a mobile phone?

[Ed CT]

You can also try a hard re-boot for the car:

1. open the trunk & wait for the car to go into sleep mode (trunk light out)
2. disconnect the neg battery cable
3. disconnect the pos battery cable
4. connect the battery cable ends together with a tie wrap or vice grip
5. turn key to pos 2 to drain any residual power
6. good time to clean the battery terminals & cable ends
7. after 5 or 10 minutes, recon pos cable, then neg cable
8. give it a try & start

[ronnie5]

You can also try a hard re-boot for the car:

1. open the trunk & wait for the car to go into sleep mode (trunk light out)
2. disconnect the neg battery cable
3. disconnect the pos battery cable
4. connect the battery cable ends together with a tie wrap or vice grip
5. turn key to pos 2 to drain any residual power
6. good time to clean the battery terminals & cable ends
7. after 5 or 10 minutes, recon pos cable, then neg cable
8. give it a try & start

I have just tried this but it didn't work, soon as I connected the battery the alarm went off. The car started fine but with the alarm still going off. The hazard lights are still flashing and the alarm has sounded for the usual 30 seconds then off. I just can't seem to disarm the alarm?

[Ed CT]

Not sure if your diamond-shaped key has the red light on it - it should light up when depressing any of the buttons. What voltage should the battery be at in your key version? IIRC it is a rechargeable version.

Next, maybe check wiring to the alarm system and leveling sensor. Could be during the week that it was parked some critters gnawed thru something.

[ronnie5]

Unfortunately it doesn't have the red light. The battery is an IIRC2025 3.5v and soldered into the circuit board. I've taken batteries out of both keys and swapped them over and both batteries are reading between 3.8-4.0v
I have a rechargeable battery in the post I bought off eBay today so hopefully that may change things when it arrives, I'm not very hopeful on this as I think the battery is fine. Thinking about it I did try a non rechargeable 2025 3.0v battery which made no difference.
Hmm.. you may even be right with the critters as I live on a farm and there are rats about, it wouldn't be the first time they have destroyed something of mine.

[Qsilver7]

You could have multiple culprits...so it may take multple attempts to narrow down where the issue is coming from.

The alarm siren has its own internal battery...and it gets charged by the car's battery. If the alarm siren's internal battery is failing, it can trigger false alarms as it interprets the low voltage as a theft attempt:

When you lock the car using the remote (or manually from the driver's exterior door lock cylinder)...what does the red "clown nose" LED do that is below your interior rear view mirror?

See the chart below as to what the various flashing means. If it indicates that a monitor is open...then the first place I'd look is the hood sensor...it is notorious for failing. Lift the hood and disconnect the wiring harness from it to see if that stops the false alarming.

Also, when the vehicle is locked using the remote or the driver's exterior lock cylinder...walk around to the fuel filler flap to see if it is locked. If it is not, then its actuator has failed or blown the fuse that is in the rear fuse block.

[Ed CT]

Hmm.. you may even be right with the critters as I live on a farm and there are rats about, it wouldn't be the first time they have destroyed something of mine.

Worth a look around. Critters have been known to mess with our stuff (I have first hand knowledge!)

I was going to ask if you've re-programmed your keys, but, if the alarm is going off as soon as the battery is connected, it sounds like an alarm system-issue. Maybe QSilver will chime in - he's knowledgeable on this stuff.

[ronnie5]

You could have multiple culprits...so it may take multple attempts to narrow down where the issue is coming from.

The alarm siren has its own internal battery...and it gets charged by the car's battery. If the alarm siren's internal battery is failing, it can trigger false alarms as it interprets the low voltage as a theft attempt:

When you lock the car using the remote (or manually from the driver's exterior door lock cylinder)...what does the red "clown nose" LED do that is below your interior rear view mirror?

See the chart below as to what the various flashing means. If it indicates that a monitor is open...then the first place I'd look is the hood sensor...it is notorious for failing. Lift the hood and disconnect the wiring harness from it to see if that stops the false alarming.

Also, when the vehicle is locked using the remote or the driver's exterior lock cylinder...walk around to the fuel filler flap to see if it is locked. If it is not, then its actuator has failed or blown the fuse that is in the rear fuse block.

Apparently you're the man with the knowledge!
The alarm doesn't go off at all until I open a door or the boot/trunk.
The unlock/lock buttons on the remote have stopped working which was the start of this problem. When I use the key in the cylinder wether I lock or unlock the door the clown nose flashes a steady red meaning armed. Only when I open the door the alarm goes off and the clown nose is flashing fast. I can drive the car like this.

I did notice that the fuel cap lock/actuator is sticking as the casing for the locking pin inside the fuel flap has cracked being brittle. With the fuel cap open and I've had a play with the pin I locked and unlocked the doors a few times with the actuator working until I close the fuel flap and it gets jammed. Maybe this is the problem? But the alarm didn't disarm when the flap was open and actuator working. All fuses are ok in the boot/trunk and the same on the glove box.

[ronnie5]

You could have multiple culprits...so it may take multple attempts to narrow down where the issue is coming from.

The alarm siren has its own internal battery...and it gets charged by the car's battery. If the alarm siren's internal battery is failing, it can trigger false alarms as it interprets the low voltage as a theft attempt:

When you lock the car using the remote (or manually from the driver's exterior door lock cylinder)...what does the red "clown nose" LED do that is below your interior rear view mirror?

See the chart below as to what the various flashing means. If it indicates that a monitor is open...then the first place I'd look is the hood sensor...it is notorious for failing. Lift the hood and disconnect the wiring harness from it to see if that stops the false alarming.

Also, when the vehicle is locked using the remote or the driver's exterior lock cylinder...walk around to the fuel filler flap to see if it is locked. If it is not, then its actuator has failed or blown the fuse that is in the rear fuse block.

I have tried the hood sensor which seems to be ok.

[ronnie5]

Worth a look around. Critters have been known to mess with our stuff (I have first hand knowledge!)

I was going to ask if you've re-programmed your keys, but, if the alarm is going off as soon as the battery is connected, it sounds like an alarm system-issue. Maybe QSilver will chime in - he's knowledgeable on this stuff.

I will do that for sure!
I have tried to re-program the key many times but I'm guessing the alarm is not allowing me to do it?

[Ed CT]

I have tried to re-program the key many times but I'm guessing the alarm is not allowing me to do it?

Yes, may not be able to re-prog keys with alarm going off. But, QSilver7 did chime in, so, let us know if that hood switch was the culprit.

[ronnie5]

Yes, may not be able to re-prog keys with alarm going off. But, QSilver7 did chime in, so, let us know if that hood switch was the culprit.

The hood switch seems to work ok. The alarm only goes off when I open a door.

[Qsilver7]

If all of the sensors seem to be working and aren't the culprit...then I'd take another look at the alarm siren itself. If it is sounding off when being deactivated...as previously mentioned...its internal battery may be failing or needs a charge.

The alarm siren's rechargeable battery is only charged when the car is NOT LOCKED. So if the car is always locked, then it is not getting recharged and may be interpreting the drop in voltage as a theft attempt.

[Ed CT]

If all of the sensors seem to be working and aren't the culprit...then I'd take another look at the alarm siren itself. If it is sounding off when being deactivated...as previously mentioned...its internal battery may be failing or needs a charge.

The alarm siren's rechargeable battery is only charged when the car is NOT LOCKED. So if the car is always locked, then it is not getting recharged and may be interpreting the drop in voltage as a theft attempt.

This is an interesting fact to know. My 21+year old car with 219k miles spends more than half of its life unlocked in the garage. Even tho it is my daily driver, it's basically parked & unlocked in the garage for for more than half the day. May explain why never an issue with the alarm battery.

Ronnie5 - maybe you just need to leave the car unlocked with a good main battery charge for a spell?

[ronnie5]

The problem I have is I can't disarm the alarm at all but I will definitely look at leaving the car unlock for at least a good 12 hours. I can't do that at the moment as I am working. Monday will be the day I could do this for the longest period. Hopefully this will sort the issue? Would be nice to actually use the bimmer.. I appreciate everyone's help on this and I will post the outcome next week.

[Aubergine]

At the risk of asking a dumb question... can the siren battery be changed? I don't want to lose my wolf whistle but the more I read, the more I think this is my issue.

[ronnie5]

I'm not sure about that? I would of thought you couldn't change these but I may be wrong? Could be the same as the key fob where you have to solder a new rechargeable battery in to it? If you could just pop the battery out it would make the car easier to steal! I'm guessing you are having the same problems as me?

[Aubergine]

I'm not sure about that? I would of thought you couldn't change these but I may be wrong? Could be the same as the key fob where you have to solder a new rechargeable battery in to it? If you could just pop the battery out it would make the car easier to steal! I'm guessing you are having the same problems as me?

The PO of one of my E39s took the alarm fuse out so i only have remote locks and lights that flash. When I put the fuse in and armed the car the alarm started going off about two minutes later. I have not had a chance to dig much further but I am thinking it could be that. The fuel door actuator and hood sensor both seem fine... but I need to spend some time and see what my code reader says.

[mattmar1]

that the fuse had been pulled out for a period of time tells you that the battery had not been charged at all for that time.

[Aubergine]

that the fuse had been pulled out for a period of time tells you that the battery had not been charged at all for that time.

Ohhhh. Yay.... So the battery is not replaceable then either?

[ronnie5]

Ok so I have had the doors unlocked for about 6 hours I also replaced the rechargeable battery in the key but I am still getting the same problem. Also I cannot program the key no matter how many times I try.
The alarm does not go off at all unless I open a door, I just can't get the alarm to turn off so I can get it and drive off.

[ronnie5]

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Also should I be getting a current from the central locking without using the locks? I can take the 7.5amp fuse out and the central locking still works when I put the key in the door.