[veemacks]

I was wondering if anyone knows how long the timeout period is for the BMW keyfobs to realize they've been set down somewhere and should stop sending out the comfort access signal?

Background to the question:

One thing people are concerned about regarding comfort access is that criminals using signal boosters can amplify the periodic signal your keyfob sends out trying to reach the car that basically indicates "I'm close enough now so that comfort access should be possible" and the car responds appropriately.

I understand that BMW have implemented a motion sensor into their newer keyfobs so that if it senses no movement for a period of time, it stops sending out that signal, thus foiling the criminals strategy. They can't boost a signal that's not being sent.

Mercedes did this in a simpler way, you simply double-press the lock button when locking the car and that told the keyfob to not send the signal out. That meant that when you come back to the car you don't have comfort access though.

The BMW solution is more expensive but more useful. You don't lose comfort access functionality as long as you're moving around enough to keep the motion sensor convinced it's not inactive.

Btw, I wish Bimmerpost had a general BMW section to post questions like this that aren't specific to the model of BMW I have. It's limiting the audience of the question quite a lot.

[Stone_M6]

Originally Posted by d4006

I was wondering if anyone knows how long the timeout period is for the BMW keyfobs to realize they've been set down somewhere and should stop sending out the comfort access signal?

Background to the question:

One thing people are concerned about regarding comfort access is that criminals using signal boosters can amplify the periodic signal your keyfob sends out trying to reach the car that basically indicates "I'm close enough now so that comfort access should be possible" and the car responds appropriately.

I understand that BMW have implemented a motion sensor into their newer keyfobs so that if it senses no movement for a period of time, it stops sending out that signal, thus foiling the criminals strategy. They can't boost a signal that's not being sent.

Mercedes did this in a simpler way, you simply double-press the lock button when locking the car and that told the keyfob to not send the signal out. That meant that when you come back to the car you don't have comfort access though.

The BMW solution is more expensive but more useful. You don't lose comfort access functionality as long as you're moving around enough to keep the motion sensor convinced it's not inactive.

Btw, I wish Bimmerpost had a general BMW section to post questions like this that aren't specific to the model of BMW I have. It's limiting the audience of the question quite a lot.

BMW has not publicly disclosed the exact timeout period for their keyfobs to stop sending the comfort access signal when motion is not detected. However, it is generally believed that the timeout period is somewhere between a few minutes to an hour, depending on the specific model and year of your BMW.

The motion sensor feature in the BMW keyfob is designed to prevent relay attacks, which involve criminals using signal boosters to extend the range of the keyfob's signal to unlock and start the car. By stopping the transmission of the comfort access signal when the keyfob is not in motion, the risk of such attacks is significantly reduced.

However, if this is a concern for you, then I suggest the following.

https://www.autowatch.co.uk/veh-sec/ghost-2-menu

Happy Installing!

[veemacks]

Originally Posted by Kol_X3Mlite

BMW has not publicly disclosed the exact timeout period for their keyfobs to stop sending the comfort access signal when motion is not detected. However, it is generally believed that the timeout period is somewhere between a few minutes to an hour, depending on the specific model and year of your BMW.

I might do a test. Tape my keyfob to the rear window and try ever decreasing time periods, start at an hour and binary chop it each try. Where my car is normally parked there's no reason to be worried about that.

Originally Posted by Kol_X3Mlite

However, if this is a concern for you, then I suggest the following.
https://www.autowatch.co.uk/veh-sec/ghost-2-menu
Happy Installing!

I'm not overly concerned, I just wanted to have that knowledge. I have a faraday pouch and the car has a tracker on it which gives me app notifications. I think that ghost thing is overpriced and a bit overkill too.

[avi66]

Originally Posted by Kol_X3Mlite

However, if this is a concern for you, then I suggest the following.

https://www.autowatch.co.uk/veh-sec/ghost-2-menu

Happy Installing!

Although be aware that in the UK installing a device like this that isn’t BMW approved may cause issues if you have a warranty claim.

Long thread from a UK member who had major issues with warranty having installed a Ghost.

[BlueCr0w]

It is 2 minutes. After closing the car and leaving the key at home (without touching it) it stop emmiting any signal after 2 minutes.

[ADIUK]

Agree 2 minutes.
Tested by leaving the key on top of rear offside tyre.

[veemacks]

Originally Posted by BlueCr0w

It is 2 minutes. After closing the car and leaving the key at home (without touching it) it stop emmiting any signal after 2 minutes.

Originally Posted by ADIUK

Agree 2 minutes.
Tested by leaving the key on top of rear offside tyre.

Thanks That'll be easier to try than 60 or 30 minutes

[Shaun170]

Doesn’t matter anymore about sleeping keys. This is no longer the current method. Latest in the UK is to plug into the cars electrical system with a device that overwhelms the electrical system and as everything’s connected via can-bus this gives access to the car etc, deactivates the alarm. Common connection points are via the rear reversing camera or the rear of the headlight via the access panel in the inner wheel arch.

No need for key signals or relays.

[veemacks]

Originally Posted by Shaun170

Doesn’t matter anymore about sleeping keys. This is no longer the current method. Latest in the UK is to plug into the cars electrical system with a device that overwhelms the electrical system and as everything’s connected via can-bus this gives access to the car etc, deactivates the alarm. Common connection points are via the rear reversing camera or the rear of the headlight via the access panel in the inner wheel arch.

No need for key signals or relays.

Good to know, I hadn't heard about that one. Glad my tracker isn't plugged into the electrical system

I was only a little bit concerned about the relay method and wanted to hear about the motion sensor timeout. Now I know it's 2 minutes I really won't need to be concerned about whether I should use that faraday pouch when I'm parked close to where the key is (like I was at Christmas, parked right outside the cottage I was renting). I had a Mercedes at that time and double-pressed the remote to disable comfort access.