Sounds like your car probably shipped with a MID unit, and it was removed to fit the aftermarket unit. If the aftermarket unit is an Android unit, there may be some other options (iBus app and connections).

The MID unit uses a single 12-pin connector (black, I think): -

https://i.ebayimg.com/images/g/a38AA...x/s-l1600.webp

https://www.ebay.com/itm/175794822768

Hopefully the MID cable is still there and hasn't been canalbiles to fit the aftermarket unit. It shouldn't have been, as the MID carries not audio signals, only data. All the audio connections would have been in the in-dash CD Player unit, which actually houses the radio and audio circuitry as well.

And yes, the CODE bypass that removes the fuse WILL sound the alarm... for a short period. Not ideal... sorry, should have warned you of that. :rolleyes:

There is a way to cancel the alarm, rather than waiting for it to shut off, but I'm guessing you are looking for a way to use the car, not simply get it to a more convenient location? In which case, the MID or iBus software etc. might be your best bet.

If you know anyone else locally with a MID-equiped E53, , you only need it for a few minutes. ;)

Been there, done that - when my ignition switch failed (start position only).

I ran a wire up from the low current terminal of the starter motor and to use the car, I would turn the ignition on, then open the bonnet (hood), short the wire to the +ve jumper terminal to engage the starter and start the engine. Worked a treat and only required one person. Used it like that for a few days until the new ignition switch turned up. :thumbup:

That's very useful information, I have the plug for that MID socket (mine is white) but didn't have a MID unit because the original NAV unit is same dimensions as my aftermarket one.
there are some similar X5's near me maybe its time to don my nice voice and knock on a few doors, as you say its only needed for a few minutes.
My head unit is identical to original but has SD slots for input source and nav updates.
I have every connector still attached behind the unit (no damage at all)

concerned that the MID units I see on Ebay uk list for radio display when my NAV unit included radio display.

Do we know if its the BC button on a MID that allows CODE entry?

BTW thank you for all the comments/advice so far - great forum

All e53 have pretty much the same equipment "hole" in the dash but some shipped with a CD Player and MID combo, while others had a full NAV screen system. If you have a MID cable in there and your aftermarket stereo is wired to audio cables in the dash (no long extension to an audio unit in the boot/trunk), your car likely had a CD Player and MID from the factory.

https://www.dvdgpsnav.com/blog/wp-co...oem-radio.webp

The MID has a row of buttons and the display indicates what each button does in each mode - to enter the code, the buttons are numbered 0-9.

Here's an older thread discussing the same issue as you have. The missing images in one of my posts are these these: -

https://i.ibb.co/MDywCZTx/MID-Code-01.jpg
https://i.ibb.co/MjDfVzn/MID-Code-02.jpg

BTW, it seems that this mode is likely triggered when a someone disconnects the battery while the key is in the igntion.

Always make sure the key is on the workshop bench or in your pocket when disconnecting the battery!

Thanks again for the information, I have no choice but to acquire a MID unit and see if that will work, (ordered from company in Ireland will take one week)

I have the handbook that has the information as shown above but it says nothing about entering a code when you don't have a MID unit. (I got an original NAV unit from a former BMW mechanic who stated his did not have a MID unit from factory (same as mine) The asterisk in the MID section title denotes it is an option.

Had the BMW software been able to connect to my car that mechanic would have been able to enter the code or remove the immobilizer function (not a good idea) - but that was not possible.

btw the local BMW dealers (Halliwell Jones) quoted 6 weeks to book in a diagnostic check

Have you tried the RESET function on cluster hidden menu?

No I haven't as I do not know what that is or how to enable it.

Can you enlighten me?

incidentally I should have the MID unit some time tomorrow

Search for instructions how to enter cluster hidden menu. Then first unlock the locking with the sum of your VIN 5 last digits. Then scroll to last function which is RESET and activate it. The cluster should boot to default values.

Thank you, I will search now. nobody mentioned that to me - not even BMW mechanics