[wayne1234]

Morning All,

Sorry if this is the wrong location for this post.

My BMW Key Fob isn't working to unlock / Open the vehicle. Starts perfectly through.

I have to use the master (Mechanical Key to open the car - which sets off the alarm).

Now, I have done a lot of investigation work, which now has me scratching my head :-(

Things I have done.

> All fuses related to the door access are OK.

> Key Fob Battery is reading just over 3v.

Antenna Diversity Unit.

>Pin 1 = 12v

>Pin 2 = 4.5v

> Pin 3 = 4.5v

> Pin 4 = 12v (When Door activated).

These voltages were measured at the antenna - Cover off.

No fault codes relating to the Door Access.

Is there anything I am missing here? I do have full access to ISTA+.

Cheers

[P14kle]

Broken wires in loom. Guessing you have a an E91 (Touring)

If so, it will be broken wires in the right hand side rubber gaitor that can be seen when boot hatch is open.

The only remedy is to slice open the rubber boot, and repair the snapped wires and re seal the best you can.

The Saloons E90 can suffer from broken wiring too, but im not sure where the wiring is on those having never owned one.

Do a Search on Google or here for more help. Its a common problem.

[Arch Stanton]

could also be the diversity module in the rear spoiler, water gets in there and corrodes them even though look ok. they ar easy enough to get at and they open up easy enough to check for corrosion

[michaelalex17]

Originally Posted by P14kle

Broken wires in loom. Guessing you have a an E91 (Touring)

If so, it will be broken wires in the right hand side rubber gaitor that can be seen when boot hatch is open.

The only remedy is to slice open the rubber boot, and repair the snapped wires and re seal the best you can.

The Saloons E90 can suffer from broken wiring too, but im not sure where the wiring is on those having never owned one.

Do a Search on Google or here for more help. Its a common problem.

This was my exact problem as well

[Runnin'Rich]

Don't slice open the rubber!

Simple pull it away from the body side and slide it down the wires to expose the damaged section. Repair the damaged section and slide it back

[Runnin'Rich]

Does the lock/unlock button work on the dashboard?

You're voltages are in-line with a good working unit, but maybe your module is still bad?

Definitely worth checking the wires

[DCD_F80M3]

Wiring harness is a good place to start.
If you have access to ISTA, you should be able to check to see if a valid lock/unlock signal is being received.