[bmwm-power]

Hi guys

sorry if this has been discussed but couldnt find any direct answers

mate of mine has a slight problem thought id ask on here for him
he recently bought a e90 airbag and seat belt light were on dash
did various searches on net
on board computer was saying cc id 97 but had it diagnosed on obd reader and it came back as 93b2 safety battery terminal

did a quick seach on you tube and found this

so we know what it is
question is how do you fix the problem? and roughly how much is the cost for parts ££..has anyone had a similar problem. the Mechanic who did the diagnostic said hes had loads of bmw's come in with the same code so must be a common issue?

is here any d.i.y bypasses available or can the battery terminal be bought from the dealership and is it a easy diy fit
has anyone done any quides?

thanks in advance

[Metalmickey]

Seen a lot of Range Rovers with this fault ( they use a lot of BMW systems). Quite often on them it's the little connector to this unit that comes unplugged, be worth checking around positive terminal on battery to see if anything disconnected or badly connected!
If not I'm sure you can replace this easy enough.

[bmwm-power]

ok cheers mate, we will have a rummage around tomorow and see if we can find anything. You maybe right i read somewhere else that there is a wire that plugs in somewhere behind the boot lining near the battery that can usually get disconnected so hopefully its something small and silly like that.
Will give bmw a ring aswell and see if they sell that BST seperatley ...i dread the thought/cost of replacing the whole positive wire to the front of the car. surely there must be a way to cut/splice in a replacement

[makkan00]

Originally Posted by bmwm-power

ok cheers mate, we will have a rummage around tomorow and see if we can find anything. You maybe right i read somewhere else that there is a wire that plugs in somewhere behind the boot lining near the battery that can usually get disconnected so hopefully its something small and silly like that.
Will give bmw a ring aswell and see if they sell that BST seperatley ...i dread the thought/cost of replacing the whole positive wire to the front of the car. surely there must be a way to cut/splice in a replacement

ALL BMW E9x come with BST.
There are two battery connectors. One carries power to essential parts only and other passes through BST and goes to DME, and other modules.

In case of accident, ABG (airbag) module triggers BST and it explodes, therefore disconnecting fuel pump and many other vital elements of the car which can lead to fire.

It is a safety feature. Once triggered, you can only start the car bypassing BST (for short term only). Error will stay on the dash till you change the BST. If you do not, and gets involve in another accident, no airbag will deploy and your safety will be at risk.

BMW sells it for around £105 + VAT. Check the code again and if it is BST, then get it replaced sooner than later. There is NO point of risking life.

You could try breakers though most of their cars are involved in accident and they sell faulty BST.

[bmwm-power]

cheers mate theres a print off of the diagnostic the code is 93B2 Safety Battery Terminal

i rang up my local dealer was quoted approx £31 + vat for the BST (red box thing on the battery) but was advised to buy the battery cable aswell at £90 ish + vat !!

surely we dont need the whole cable?.. should be able to just pull out/unplug the old cable and slot into the new BST. has anyone changed theres...any guides available. I rang my local bmw breaker and he said that the BST can be changed on its own.

[makkan00]

Originally Posted by bmwm-power

cheers mate theres a print off of the diagnostic the code is 93B2 Safety Battery Terminal

i rang up my local dealer was quoted approx £31 + vat for the BST (red box thing on the battery) but was advised to buy the battery cable aswell at £90 ish + vat !!

surely we dont need the whole cable?.. should be able to just pull out/unplug the old cable and slot into the new BST. has anyone changed theres...any guides available. I rang my local bmw breaker and he said that the BST can be changed on its own.

I have not seen your posted video and I am not sure what is in it. (internet is playing on my side, otherwise would have looked at it).

There is a lot of wrong info on the internet. If you are having BST code, it is not related to BST box, but the red cable.

That cable runs from the battery to BST box and that becomes faulty.

You'd require the new battery cable, not the box. Box itself has only fuses in it and it works like a distribution box (in audiophile world).

As your breaker said, BST can be changed on its own, but that does not develop fault at all.

Go for red cable and after changing it, you'd require a code resetter to reset the code.


If you are not sure, take out BST box. Open it from underneath and see inside. If any metal plate is fused / melted, then BST box is your target. 90% it is BST cable.

HTH.

[bmwm-power]

the video is on youtube if you are finding the link doesnt work just search for bmw BST diagnosis.

were going to take it apart on friday and see if we can spot something obvious before buying anything.

[tboudre]

I just happened to have a 1-ohm 10-watt wire wound resistor. There's really no need to do all the soldering like the gentleman in the video:

on a 2011 3-Series. Mine looked like the one in this french video:

No need to ruin the plug if you plan on repairing the BST in the future, just shove the leads to the resistor into the plug as shown. My error clears with the resistor and comes back with plugged in properly. I've tried jiggling the wire all around. I measured 0.7 ohms on the BST pins, but with the 1-ohm resistor, there is no error.
My only concern would be if the restraint system did fire the BST with the resistor in place you'd be looking at 12-14 amps on those tiny wires which would be 144 to 196 watts. I'm assuming that after the charge blows you would have an open circuit, but with the resistor in place, the circuit may stay active until the resistor is fried or a fuse blows or the wires melt. In the video, he uses a 1/4 to 1-watt resistor, which would likely fry and open up pretty quickly if the system fires the BST.
As you can see from the pictures I taped mine up and secured it.
BTW I used "Bimmerlink" to clear my codes. The price was reasonable, I think about $20 U.S. It's a Beta, but it does have the error code descriptions built-in.