Check your V24 system CD. Check it burned as mode2 (use NeroTools or ImgbBurn). Check it burned with no errors. Mount image in a virtual drive and check all files in your DC against those in the image.

Eject and withdraw any disc from your navigation unit. Switch your car off and withdraw the key. Open your trunk and gain access to your battery. Do not open or close doors. Do not use your remote. Wait for all the systems to shut down -it may take some 5 or 10 minutes. All interior and trunk lights should have gone off and more specifically the navigation unit LED should have gone off. Disconnect ground cable from your battery once you are sure all systems have shut down. IMPORTANT: Disconnecting battery while MK-III is still shutting down may permanently disable the unit.

Wait for some 30 minutes. Re-connect your battery. Turn key to pos 1. Wait for all systems to boot and stabilise. Wait for your screen to fill and display whatever it does display. Check if you still have no navigation in your main menu –just in case.

Now insert the V24 disk and wait. Do not touch the key. Do not open or close doors. Do not touch the car nor your remote. Wait for hours if need be until the CD will be ejected on its own and the screen will ask you to press OK (right button). When that happens, remove the CD and press the button. Then wait for the system to reboot. Do not touch the key until it has rebooted.

If all fails: See if you can test your MKIII unit in a friend's car or try a friend's unit in your car. Eventually check that I-Bus wire is not cut.

I really can not think what else can you do.

If the unit was permantly disabled would it still take the disc and spin etc
Just wondering because i have disconnected the batery a few times

Is Mk4 a straight swap???
If my Mk3 is dead i mas a well buy a Mk4 unit

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2005 E53 4.4 sport

Quote from BMW document:

SITUATION: The MK3 Navigation computer powers down in approximately 60 seconds after the ignition has been turned OFF (red LED on the computer goes OFF). If the power supply to the MK3 unit is interrupted (by removing/disconnecting the computer from the vehicle, or by disconnecting the vehicle's battery) in the time period of 55 to 57 seconds after the ignition has been turned OFF, the power-down procedure ("erase and save data in Non Volatile RAM") can be corrupted. This will result in a total failure of the MK3 computer (red LED off, CD eject function inoperative, board monitor screen permanently blank, and no sound from the audio system). In such a case, the navigation computer has to be replaced.

CORRECTION: On vehicles with MK3 navigation system, prior to disconnecting the battery or removing (disconnecting) the Nav computer, make sure the MK3 Nav computer is in the power-down mode (red LED on the unit is OFF).

End of quote

Not a great chance that power off happened exactly at the wrong moment. I think it is something to be careful about in the future but nothing to fret about what may have happened in the past. And then again “total failure” as far as the dealer is concerned does not mean it can not be recovered by more imaginative individuals.

Anyway your system does not show the right symptoms for a dead unit. I would not lose faith.

I borrowed a genuine BMW V28 OS disc from my local dealer and still no luck
Disc has been in the car now for 2 hours GRRRRRR

What does the ibus wire look like

I have followed the instructions exactly
The unit takes the dics and then makes a few wiring noises and then nothing.
It dosent sound like the disc is even spinning

P.S. Thanks for everones help so far!!!!!!

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2005 E53 4.4 sport

The I-Bus wire is white and red with some yellow. You should find it in the connectors to the Mk-III unit. You could use a voltmeter and check if it has a voltage of some 12V (maybe a bit less if there is I-Bus traffic).But to be honest I do not think the problem lays there. It would seem the unit can not read a CD, no matter if it may also not be able to communicate. I'm out of ideas now, really. Maybe the unit has hardware problem and maybe someone with more experience can help you further.

Hi Crombo97,

It is easier to diagnose the nav by monitoring the ibus traffic. Do you have the ability to do that? You will need an ibus adapter and some software - my Navcoder program works well, as does WinBus.

I also have a Mk3 (and a Mk4) here in Auckland NZ and have been writing diagnostic sioftware for these units.

If you here a few wirring noises then the disc is trying to spin. Maybe your laser is dirty? Maybe the disc is scratched?

These things, and the ibus status, are easy to figure out on my workbench!

If you want to, you can post the mk3 unit to me for a look-see. I can send it back to you afterwards. Email me if you are interested,

Thanks for the offer!!!
It sounds like a great idea.
Can you PM me your address and ill post it to you.
I opened the top cover last night to see if the disc was spinning and it does spin after it is loaded but then stops after a minute or so.
It makes the wiring sound as it is spining like it cant read the disc.

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2005 E53 4.4 sport