SRS air bag light on

Well here we go again, i have a 2004 4.4 petrol, i have been helped my so many people so far i have lost count of how many threads i have started.

recently removed the transmission and although i am back up and running mostly i have the air bag light on the dash illuminated.
it blinks briefly when i turn on the ignition.

all comms diagnostics says 'battery disconnect unit 1', and if i try and clear the fault it goes for a second and then comes back again.

i have read a few posts that recommend disconnecting the battery for a few minutes but every time i have disconnected my battery recently i have to get a main dealer to re establish the engine / immobiliser link else there is no way it will start.

if the SRS BCU is under the hand brake panel then this could point to other faults as my transfer box is also dead with the switch doing nothing and also my hand brake warning light only works when the hand brake is off and i push down on it

any ideas much appreicated

I am sort of answering my own post here, but i thought the all comms message meant that the SRS unit 1 had the battery disconnected but after reading rave the 'battery disconnect unit' is the unit that explodes and disconnects the battery if that helps which i think is what saint was saying in another post

if i disconnect my battery it will most probably not start, if i try and work on the disconnect unit with it connected it may take my face off a bit

holidaychicken said:

I am sort of answering my own post here, but i thought the all comms message meant that the SRS unit 1 had the battery disconnected but after reading rave the 'battery disconnect unit' is the unit that explodes and disconnects the battery if that helps which i think is what saint was saying in another post

if i disconnect my battery it will most probably not start, if i trey and work on the disconnect unit with it connected it may take my face off a bit

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Yep that's the bit I was talking about...

Also as I said in the other post, oftentimes, I leave SRS related issues to a Dealer, I know after tha outlay you have you want to recoup before more expenditure...but they can inspect the unit safely, and recode it if it fails to start again.

Do you have an MOT due soon??

Saint.V8 said:

Yep that's the bit I was talking about...

Also as I said in the other post, oftentimes, I leave SRS related issues to a Dealer, I know after tha outlay you have you want to recoup before more expenditure...but they can inspect the unit safely, and recode it if it fails to start again.

Do you have an MOT due soon??

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if its not something obvious it will be back to the dealer again and yes its due the end of November.
if i was brave i would try to disconnect the battery and re connect but you know what will happen so it may as well go to the dealer anyway at least under its own steam..

My SRS occasionally comes up. But mine is a faulty / loose connection somewhere under the passenger seat that I'm still trying to find.

Usually only happens after you adjust the seat.

Obviously when you clear the faults it just comes back up again ??

From what I can gather, there is no sensor in the Battery Disconnect Charge, so the fault is either the SRS detects a fault in the wiring to the charge, or it thinks it has fired the charge.

2.0_Hippo a while ago had issues with his SRS system constantly giving a 'Crash' signal that he couldn't clear or find with the All Comms, hence why he went out and bought the much loved (and sodding expensive) Faultmate Extreme to dig even deeper than most other devices - including the Testbook!!

Can't remember what his resolve was though!

2.0_hippo said:

My SRS occasionally comes up. But mine is a faulty / loose connection somewhere under the passenger seat that I'm still trying to find.

Usually only happens after you adjust the seat.

Obviously when you clear the faults it just comes back up again ??

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Thanks, Do you get chance to get a fault code when it comes on?

yes when i clear the fault the light blinks and then comes straight back on.

the new look of your facelift is great, i'd like to do something similar if i ever iron out all my faults

Saint.V8 said:

From what I can gather, there is no sensor in the Battery Disconnect Charge, so the fault is either the SRS detects a fault in the wiring to the charge, or it thinks it has fired the charge.

2.0_Hippo a while ago had issues with his SRS system constantly giving a 'Crash' signal that he couldn't clear or find with the All Comms, hence why he went out and bought the much loved (and sodding expensive) Faultmate Extreme to dig even deeper than most other devices - including the Testbook!!

Can't remember what his resolve was though!

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just read your post after answering 2.0_Hippo's, my drivers side seat surround is a bit cracked where its been lent on to get out.
i have a few other issues under the centre console so i might pull that apart and see whats going on under there as well.
i wonder what might happen if i disconnect the disconnect unit from the yellow multi plug and connect back up again.
i read up in rave how it works by firing a plunger inside the unit to disconnect the supply and the plunger gets caught behind a non return catch, quite clever really

holidaychicken said:

just read your post after answering 2.0_Hippo's, my drivers side seat surround is a bit cracked where its been lent on to get out.
i have a few other issues under the centre console so i might pull that apart and see whats going on under there as well.
i wonder what might happen if i disconnect the disconnect unit from the yellow multi plug and connect back up again.
i read up in rave how it works by firing a plunger inside the unit to disconnect the supply and the plunger gets caught behind a non return catch, quite clever really

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The cracked plastics on the seat shouldn't cause any issues.

Don't unplug the seat connectors without disconnecting the battery and allowing the electrical system to drain of power.

As some of the connectors under the seat will be for air bags and other bits for the SRS system. Disconnecting them whilst live could be catastrophic ! Lol

holidaychicken said:

Thanks, Do you get chance to get a fault code when it comes on?

yes when i clear the fault the light blinks and then comes straight back on.

the new look of your facelift is great, i'd like to do something similar if i ever iron out all my faults

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Yes. Well sometimes.

At the moment when my SRS light comes on it only lights very dim... So there's a loose connection somewhere causing it to "nearly" go into fault mode. But it's not enough for the diagnostics to get a fault code off.

When I did get a code, it was related to one of the occupancy sensors in my passenger seat.

My "crash mode" problem I had last year magically cleared itself!

I think it was a fault within the BCM as if it was a crash sensor that had triggered then it would have deployed the relevant airbags !! Lol

2.0_hippo said:

Yes. Well sometimes.

At the moment when my SRS light comes on it only lights very dim... So there's a loose connection somewhere causing it to "nearly" go into fault mode. But it's not enough for the diagnostics to get a fault code off.

When I did get a code, it was related to one of the occupancy sensors in my passenger seat.

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I would think a dimly lit bulb is an earthing issue....you may have a stray earth somewhere if there is no fault logged...

As far as I know, the lamp is either on or off with no graduations inbetween indicating 'level' or 'probability' of fault...I wonder hamper a guess at a loose bulb holder or stray earth somewhere!

2.0_hippo said:

Yes. Well sometimes.

At the moment when my SRS light comes on it only lights very dim... So there's a loose connection somewhere causing it to "nearly" go into fault mode. But it's not enough for the diagnostics to get a fault code off.

When I did get a code, it was related to one of the occupancy sensors in my passenger seat.

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well at least it was pointing you in the right direction, these cars like to make you work with so many systems linked together

do you have the faultmate and if so which one?

i looked on their site this morning and they didn't look horrendously expensive, i quite like the look of the nano that works with a laptop but i have sold all the body parts that i don't need so it might be a while before i can afford it

Hippo has the Faultmate Extreme MSV2 - about £1000+ EDIT: £950 odd according to BBS

Does the Extreme Nano cover the L322?? I think that is around the £650 mark or so I think! EDIT: Yep they do the Nano Server for the L322 at e1030 odd Euros...which is around £894 odd

I know they don't currently do a Nanocom for the L322, which is what Iwill save up for when they do!

Saint.V8 said:

Hippo has the Faultmate Extreme MSV2 - about £1000+

Does the Extreme Nano cover the L322?? I think that is around the £650 mark or so I think!

I know they don't currently do a Nanocom for the L322, which is what Iwill save up for when they do!

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Last time I looked Ant, there was not a huge difference in price about €60 between the Faultmate Nano and the Faultmate Extreme. The Extreme is worth the extra IMO as you can use it without a laptop.
Roughly €1031 for the Nano, €1095 for the Extreme.

Datatek said:

Last time I looked Ant, there was not a huge difference in price between the Faultmate Nano and the Faultmate Extreme. The Extreme is worth the extra IMO as you can use it without a laptop.

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Thanks Keith - just edited post above after looking at their site

Saint.V8 said:

Thanks Keith - just edited post above after looking at their site

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i was looking at the prices at the link below under the hardware tab, the kits are way over my budget of £0

https://blackbox-solutions.com/shop/

+1 yes.
Might as well and pay the extra £££ and get the extreme with the built in display.

I got the full fat extreme with full capability for all of the different modules.

Think it came in at around £1,100 after delivery and tax expenses

Great bit of kit! No fault worries me now

2.0_hippo said:

+1 yes.
Might as well and pay the extra £££ and get the extreme with the built in display.

I got the full fat extreme with full capability for all of the different modules.

Think it came in at around £1,100 after delivery and tax expenses

Great bit of kit! No fault worries me now

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maybe one day, i cant see how anyone could own an l322 and not have some form of diagnostic kit. my allcomms is quite good for the money i reckon.

is the airbag light on an MOT fail?

holidaychicken said:

i was looking at the prices at the link below under the hardware tab, the kits are way over my budget of £0

https://blackbox-solutions.com/shop/

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That is just for the unit - that doesn't include the license for the software or the connection leads(?) - which is where the price of the kits comes in to play....expensive but worth it!