Automotive Bluetooth Systems

[Mickt]

Dear Bluetooth Gurus,

I've recently been looking at purchasing a new vehicle and have found that vehicle bluetooth systems in a number of those small cars we've checked out, e.g. GM, Skoda, Hyundai and VW brands, the Bluetooth is always on – as advised by the respective manufacturers.

We want to be able to turn off or disable the vehicle bluetooth system to avoid any bluetooth emissions (noting that mobile bluetooth will also be switched off).

Our reasons for this aside, from a technical perspective I would have thought that if I had my phone bluetooth on and visible to any bluetooth source I should be able to see any vehicle bluetooth system that may be on, i.e. the vehicle I'm in and any others within my immediate proximity with their bluetooth on.

Is this a reasonable proposition or could a bluetooth system be on but not visible to me if my phone was unpaired?

Any assistance by way of a response would be very much appreciated.

Cheers,

Mick
(still looking and test driving...)

 

[Syntax42]

What are you worried about... someone hacking your MP3s through bluetooth? The devices need to pair to talk to each other and if you don't put your car in pairing mode, nobody will be able to hack your car, theoretically. I use that term because there are no public records of bluetooth vulnerabilities aside from intercepting the pairing keys at the moment of pairing.

 

[Someone Somewhere]

Bluetooth is able to be on but not visible. Most device spend almost all time in this state - they only connect when a pre-paired device comes in range. It must be set to visible to be paired with.

Different carsystems have different ways of making them visible and able to pair, but it depends on manufacturer. Often involves either going into the menu system, active in the first minute or so after starting, or active while the key is in the ignition but not started.

 

[Mickt]

What are you worried about... someone hacking your MP3s through bluetooth? The devices need to pair to talk to each other and if you don't put your car in pairing mode, nobody will be able to hack your car, theoretically. I use that term because there are no public records of bluetooth vulnerabilities aside from intercepting the pairing keys at the moment of pairing.

It's nothing to do with hacking - just a question of disabling any bluetooth emissions. We don't need to use blluetooth and as a consequence don't want the system on. If it can be switched off that's ideal.

It seems that some dealer staff don't understand how it works when they say "you can turn it off by turning off your mobile phone" at the very least there are inconsistencies between them. Most recently we have been told that the system activates on vehicle start up and if no paired devoices are located it will stop looking after (an indeterminate period) and go into hibernation. I'm guessing that means a form of standby with emissions disabled.

So back to my original question: if I have my mobile phone bluetooth on and discoverable should I expect to see my vehicle bluetooth system if it's active? And if I can't does that mean it's off? Or, is this too simplistic and incorrect?
Thanks!

 

[Someone Somewhere]

I don't know if it would completely cease transmissions if not paired and not visible. Might still be a heartbeat of some kind. That depends on the bluetooth standard.

Is there a particular reason why you want it to completely cease transmissions?

 

[Mickt]

Bluetooth is able to be on but not visible. Most device spend almost all time in this state - they only connect when a pre-paired device comes in range. It must be set to visible to be paired with.

Different carsystems have different ways of making them visible and able to pair, but it depends on manufacturer. Often involves either going into the menu system, active in the first minute or so after starting, or active while the key is in the ignition but not started.

So if it's invisible does that mean it's not radiating?

Is invisible the same as hibernating?

There is a perception here that if the system is on then it is radiating - this has been encouraged by sales staff who clearly are not as technical as we would prefer. I underestand this may vary with different systems but it systems to be a common theme as we find out more, i.e. that the system will start up and do a quick scan for paired devices - if none found will go into hibernation and will effectively be inactive (read not radiating) until a manual command to pair or communicate is executed via the infortainment touchscreen or other user interface.

Appreciate your response

 

[Mickt]

I don't know if it would completely cease transmissions if not paired and not visible. Might still be a heartbeat of some kind. That depends on the bluetooth standard.

Is there a particular reason why you want it to completely cease transmissions?

EMF sensitivity is the reason. So to promote greater comfort the preference is to ensure that vehicle bluetooth can be disabled when that family member is in the vehicle.

You mention a heartbeat and bluetooth standard. Can you recommend further reading on this?

Thanks again!

 

[Someone Somewhere]

Oh great, people think they can feel sub-100mW microwave. Not getting into that mess. You get more from going near a cellsite, let alone radio/TV towers... or speed traps.

A heartbeat is a signal sent to check whether or not another device is (still) in range. This would be needed for two already-paired devices to connect.

The Wikipedia article, and have a look at the sources on there.

My advice would be to deny everything...

 

[teddymines]

Just tell them it is off.

 

[Mickt]

Oh great, people think they can feel sub-100mW microwave. Not getting into that mess. You get more from going near a cellsite, let alone radio/TV towers... or speed traps.

A heartbeat is a signal sent to check whether or not another device is (still) in range. This would be needed for two already-paired devices to connect.

The Wikipedia article, and have a look at the sources on there.

My advice would be to deny everything...

Simple thing to say, but the person has enough knowledge basic function but insufficient to be realistic about other radiators that would be more of an issue. I can't change that and she has to be comfortable... it's one of the things you do.

Anyway, I suspect the bottom line and the definitive test is to use a field strength meter to check and to also do a comparison to a mobile phone and phone towers to try and provide some perspective.

 

[Mickt]

Just tell them it is off.

They're already sceptical about anything like this and with dealers' inconsistency in describing how BT works it's just added further fuel to the fire. Had the dealers (not all - but most) explained function correctly in the first instance and could demonstrate it in the vehicle the issue would not be what it currently is.

So no, telling them it is off won't work.