OBD 2 Port Usage warning in the manual?

[mindmachine]

The owners manual warns us that the OBD2 port should not be used by us the owner/end user as it could cause a fault of who knows, some sort.

I was wondering if anyone is using their OBD2 port for insurance company tracking devices. Several companies offer a discount based on your driving style, but you have to mount a reader to the OBD2 port which then tells the insurance company info so they can asses your driving style and distances driven, speed, ect... I have State Farm insurance and the use their in-drive device in my cars is saving me around 20%.

I ask BMW about using the device considering the warning in the manual and they did not have an answer, just that maybe it would be at my risk.

 

[jadnashuanh]

All of the computer displays, user interface stuff (like the door locks, interior lights, headlights, taillights, etc.) are powered by a small 12vdc battery. During recharging and operation, that gets recharged from the main drive batteries via a DC-DC power supply (that doesn't run when the car is not being charged or is not in the ready state). Since that 12vdc battery is quite small, any long-term load on it could make the car undriveable, even if the main batteries are fully charged. So, anything that gets plugged into that port could be problematic. Now, there may be other reasons, but to me, that's a big one. And, since that battery isn't used to turn a starter motor, it could have its output voltage drop enough so that some stuff wouldn't work properly. If you notice, the 12vdc sockets for accessories in the car are quite low powered as well (limited to something like 2A, if I remember), which could limit what ends up working in them, too.

 

[mindmachine]

All of the computer displays, user interface stuff (like the door locks, interior lights, headlights, taillights, etc.) are powered by a small 12vdc battery. During recharging and operation, that gets recharged from the main drive batteries via a DC-DC power supply (that doesn't run when the car is not being charged or is not in the ready state). Since that 12vdc battery is quite small, any long-term load on it could make the car undriveable, even if the main batteries are fully charged. So, anything that gets plugged into that port could be problematic. Now, there may be other reasons, but to me, that's a big one. And, since that battery isn't used to turn a starter motor, it could have its output voltage drop enough so that some stuff wouldn't work properly. If you notice, the 12vdc sockets for accessories in the car are quite low powered as well (limited to something like 2A, if I remember), which could limit what ends up working in them, too.

Thanks, I know about the 12 volt computer boot up battery, I have a Prius plug in, I am wondering if there are any other things to be concerned about. The indrive app allows you to watch your 12 volt status, in my other hybrid if i don't drive the car in two weeks i have to charge the 12 volt.

 

[jadnashuanh]

A difference in the i3 is that there is no easy, safe way to just charge the 12vdc battery, it gets done while running or charging the main batteries.

 

[mindmachine]

A difference in the i3 is that there is no easy, safe way to just charge the 12vdc battery, it gets done while running or charging the main batteries.

I See. Thanks.

 

[beachfitrob]

I leave my Leaf's Bluetooth OBD II scanner plugged in all the time. No issues unless you leave the app running. The Leaf has a half size or so 12V battery.

 

[ted99]

I received one of these as a trial from my insurer. Plugged it in and the insurer's monitoring activated it. But, when I drove away to a destination, parked and tried to lock the car, the theft alarm went off. Turned off alarm by unlocking with the key fob. Repeated, same result. Removed monitor and everything went back to normal. Sent the monitor back to monitoring company with explanation of problem. No contact since.

 

[GodFollower]

Vouching what Ted said. Beyond the power draw these devices can incur they also interfere with the ethernet communication of the vehicle. The most noticeable symptom is the alarm going off when locked; sometimes immediate, sometimes it waits 30 minutes or more before it goes off. In some cases I have also seen these monitoring devices interfere with bus communication, although in theory it should only be able to interfere with the headunit. On one vehicle is was causing the headunit to stay on when the car was shut off.

 

[jadnashuanh]

Most BMW's have so much going on with the networked computers...it can be messy when you introduce something into their network that doesn't play well. Very few of the things you think of as switches actually control the things they look like they control directly...they talk over the network and one of the computers does the actual switching. Anything that gets in there could mess with it. Stepping on any message or keeping talking on the bus can cause one thing or the other to miss a shutdown command and drain the battery.