540i E34 ECU Ultrasonic Anti Theft MODULE 836622 failed - should it affect Clock?

[lchiu26]

The key for the car died and when I opened the car without using the remote all the alarms went off and the car was immobilised. No choice but had it towed to my mechanic. They put in a new battery but the IR sender had failed. Luckily I had another key(not paired) and gave it to them.

To cut a long short after a lot of diagnostics and removing control modules this alarm module had failed and they removed it and managed to get the car to start using the key.

This is the module.

https://www.ebay.com/itm/283504956363

So that got the car working but when I picked up the car they said because they removed the module now I have no alarm which is fine. But I also have no remote unlocking which I guess is understandable.

But I also have no display on the car computer and pressing the left side indicator level no longer brings up car info like fuel usage, date/time etc.

Does this module control those functions or in their diagnostic work unplugging and plugging back modules they left some connection disconnected?

[johan750]

The OBC gets the power from this module. There is even a fuse on it for that. You could try just plugin in the two connectors with the thick pins. This could bring the OBC/clock back to life and leave the rest of the alarm inoperable.

[lchiu26]

The OBC gets the power from this module. There is even a fuse on it for that. You could try just plugin in the two connectors with the thick pins. This could bring the OBC/clock back to life and leave the rest of the alarm inoperable.

Cool, thanks. They gave me the old module to look and I do see a fuse on it. I will tell them what you said. Out of interest if I bought a new anti-theft module used would I need BMW to program it?

Just to clarify. One of the block connectors provides power to the OBC and when they removed the anti-theft module, the OBC had no power. So if they look under the seat they should see a power cable for the OBC just dangling free?

[lchiu26]

I just had another thought.Maybe because the mechanic did not know how or have the kit to program the second key he brute forced the start by removing the immobiliser. So if I took the car to a BMW dealer they could potentially program the key and check the immobiliser and re-install it?

[lchiu26]

I just had another thought.Maybe because the mechanic did not know how or have the kit to program the second key he brute forced the start by removing the immobiliser. So if I took the car to a BMW dealer they could potentially program the key and check the immobiliser and re-install it?

Just to close this loop off. I did a find another auto electrician who knows about these cars. He successfully re-installed the module, enabled the immobiliser and reprogrammed the key and remote, all in 3 hours! So everything is back to normal again. There was nothing wrong with the immobiliser at all.

[a777fan]

Just to close this loop off. I did a find another auto electrician who knows about these cars. He successfully re-installed the module, enabled the immobiliser and reprogrammed the key and remote, all in 3 hours! So everything is back to normal again. There was nothing wrong with the immobiliser at all.

Yep! Can be tough finding people who know how to work on these cars properly. Glad you fond someone and are back in business.