Ongoing airbag issue - BST cable ?? Mini GP

Ongoing airbag issue - BST cable ?? Mini GP

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Pip1968

Original Poster:

1,346 posts

203 months

Sunday 27th November 2016
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Well generally getting the airbag reset every MoT did solve it initially but now even a reset will not work. Anyway I got the code read and it came up as the battery cable. I took it to H&C Motors in Maidstone (electrical 'experts') who on booking said yes we can sort it. Well I had already told them what the problem was but they then charged me another £72 to tell me the same code that had already been read by another garage and then say I would have to book it in a some point so they could get the cable from BMW/Mini (~£200). This on top of a provisional 6 hours job to replace the cable so £650 all in.

Well having delved further it seems it may be the BST (a safety device that partially severs the battery cable in the event of a crash [or apparently even in a small bumping incident]).

My question is has anyone had to go down this route to sort their airbag light problem? There is a replacement BST for BMWs which presumably may work on a Mini and will save replacing the whole cable. The other option seems to be putting a resisitor on the cable that runs to the battery but I assume this will disable the airbag completely.

Pip

fay970l

13 posts

119 months

Friday 2nd December 2016
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Hi
We had an ongoing problem with a R52 Cooper S airbag system & spent hours changing parts etc & using a cheap coding tool. In the end we contacted Airbag Man & the guy fixed it very quickly & cheaply. This is what they do for a living rather than a general garage so might be worth you contacting them:
http://airbagman.co.uk/contacts/
http://airbagman.co.uk/

PetrolBreakfast

78 posts

151 months

Friday 2nd December 2016
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I had this problem briefly and it was apparently dust in the BST housing or connectors, not sure which. However, Harwoods in Basingstoke instead of doing what main dealers normally do and charge me for a full cable, cleaned it out, re-tested it and I'm 4000 miles on from then and all is good. They charged me £56.

Pip1968

Original Poster:

1,346 posts

203 months

Saturday 3rd December 2016
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Thank you to both of you. Very helpful.

Pip

Pip1968

Original Poster:

1,346 posts

203 months

Friday 24th February 2017
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Well I thought I would post my resolution to this little headache.

Following extensive research into fixing this ongoing problem I finally seemed to have sorted it out. On previous MoTs the light was extinguished but would inevitably come back on a week or so later. Finally it got to the stage where it could not be extinguished and the fault code came up as battery cable.
In essence this will either be the percussion cap between the positive feed/connection which has blown/become dislodged or the incorrect resistance reading by the sensor. Power leads can be fixed by either buying a new connector which has not blown or by buying a repair kit for a BMW. These have the same ‘sh#tty’ safety system in place. Oh, you can also buy a complete new positive lead that runs from battery to engine bay (expect six hours labour and another £250 for the cable) – For HSE and arse covering this is my RECOMMENDED fix and NOT the way I am about to detail.
To clarify the percussion cap for want of a word sits between the positive terminal connector on the battery and the lead that joins this and is covered by the black plastic shroud. It is designed so that if you have an accident the cap blows and the battery positive lead is disconnected. This means that you will not burn to death presumably. As a sceptic, I am not sure when I last heard of anyone burning to death in a road accident – HSE gone mad as usual.
Anyway the other remedy is to buy a 2 Ohm resistor and disconnect the sensor that sits on the positive connection to the battery. The resistor is then soldered to the two connectors on the disconnected lead and then deleting the warning code. As it is fiddly to remove the connector on the battery lead you may just want to cut it and then just tape the ends out of the way as it provides no further function. The other end that is connected to the little control box next to the battery can then have its two wires soldered to the resistor.
I disconnected the sensor from the battery positive lead in case the resistor did not solve my problem. You can solder the resistor to the plastic connector (obviously the metal wires within it). The connection on the battery can be gently prized off using a screwdriver to lever it (mine was ‘L’ shaped and there did not seem to be any locking device but it was quite firmly on). The other end of the sensor that seems to sit in a control box requires a little tab to be pushed in towards the wire part before the it can be pulled out. Failing that just solder in situ.
The consensus seems to be that the airbag will still function as the sensor’s job is to make sure the battery positive is not disconnected (and its resistance is correct). Of course you dabble at your own risk. I am not an auto electrician and most definitely NOT a HSE officianado thank God.
If anyone is Kent way and wants assistance I am happy to help.

Pip
Ps you can also buy something from ebay for £35 which is probably just the resistor in a small box with wires.