Airbag ECU to ICU ? (1 Viewer)

[Colino]

Morning all. I been thinking as I sometimes do, about airbag ECU and I have a question for the tech savvy among you.
Some people say the airbag light comes on due to a drop in voltage or a voltage variation. So what if the van was going to be parked up over the winter and I decided to literally disconnect the airbag ecu. I mean disconnect from battery and disconnect the wires that click into the side of it. Almost as if I was taking it out. I could leave the solar panel trickle charge connected to the battery to keep that charged but I wouldn't have to worry about any change in voltage through the airbag ecu.
Also I was wondering could the van be started without the airbag ecu being connected. The reason I ask this is I could just start the engine to give the battery a bit of a boost before reconnecting the ecu.
Just a thought

 

[Srp111]

It could be started but the airbag light would come on, you may need a diagnostic device to turn it off again

 

[Lenny HB]

It Can be started and run without the airbag ECU but you should never run the engine on tickover from cold as you risk serious damage to the engine. Modern diesel engines should be driven off straight away after starting.

I think low voltage failure is a bit of a mith if its going to fail it will not much you can do about it.

 

[Jimbohorlicks]

You can disconnect the ecu over winter and reconnect after starting the van again ,when the engine is off. The airbag light will go out again it doesn't require reprogramming.
Best if you also consider fitting a secondary earth to one of the holding down bolts( clean up the contact faces first to remove paint etc.)
I don't think the voltage is much of an issue, probably a bit of an easy option to blame .mine was supposed to have failed with a voltage of 12.6v? .

 

[Colino]

You can disconnect the ecu over winter and reconnect after starting the van again ,when the engine is off. The airbag light will go out again it doesn't require reprogramming.
Best if you also consider fitting a secondary earth to one of the holding down bolts( clean up the contact faces first to remove paint etc.)
I don't think the voltage is much of an issue, probably a bit of an easy option to blame .mine was supposed to have failed with a voltage of 12.6v? .

So are you saying I can disconnect the ecu over winter then before I reconnect I can start the van turn it off then reconnect the ecu.
I have already attached another earth ready for when the ecu goes back on.
Thanks Colin.

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[Jimbohorlicks]

So are you saying I can disconnect the ecu over winter then before I reconnect I can start the van turn it off then reconnect the ecu.
I have already attached another earth ready for when the ecu goes back on.
Thanks Colin.

Yes.
There are several threads where folks have done this, some have reconnected just before an MOT.

 

[gus-lopez]

could the van be started without the airbag ecu being connected.

yes & driven

So are you saying I can disconnect the ecu over winter then before I reconnect I can start the van turn it off then reconnect the ecu.
I have already attached another earth ready for when the ecu goes back on.
Thanks Colin.

yes

 

[Colino]

yes & driven

yes

So if I were to drive it with the ecu disconnected would I still get the airbag warning light.
I don't intend to, but it is interesting
Thanks Colin

 

[TheBig1]

yes the body control ecu would report a fault with the airbag ecu as it can't see it. You can drive like that but no airbags obviously

I believe Peter Larby tried disconnecting over winter but the ecu still failed again when back in use

 

[Colino]

One last question. I have an 04 fiat panda. When the airbag light came on I just bought one like for like off ebay and swopped them over. No proxy alignment. So could I buy a used one for the motorhome that has the same model number and just swap them over without proxy alignment?

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[Phill D]

One last question. I have an 04 fiat panda. When the airbag light came on I just bought one like for like off ebay and swopped them over. No proxy alignment. So could I buy a used one for the motorhome that has the same model number and just swap them over without proxy alignment?

Fiat have a proxi process which must be used to match each component ecu to the main system.
Do a spare still needs alignment

 

[Phill D]

I would suggest if you are going to disconnect over winter that for the sake of 3 nuts you remove the unit from the van and place it in a relatively temperate stable environment. You want to avoid any risk of condensation in the unit.

 

[Colino]

Fiat have a proxi process which must be used to match each component ecu to the main system.
Do a spare still needs alignment

So does that also apply to the fiat panda or is it just on the vans that they have to be proxy aligned ?
Thanks Colin.

 

[TheBig1]

if the panda is 04 it is likely a dumb system, as in not full can bus

 

[Phill D]

So does that also apply to the fiat panda or is it just on the vans that they have to be proxy aligned ?
Thanks Colin.

i dont know the panda but if its a similar vintage to your motorhome then that is likely.


Edit: just checked multiecuscan and it cover Panda from 03

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[TheBig1]

i dont know the panda but if its a similar vintage to your motorhome then that is likely.


Edit: just checked multiecuscan and it cover Panda from 03

It does but without many options available on the later system. You can even use it on a 2000 van with the 3 pin adaptor for the plug on the nearside wing. There are still garages that don't know that

 

[activecampers]

There is a shutdown and startup procedure for battery removal which ensures ECUs are powered off and on in the correct order.
Its the uncontrolled shutdowns (pulling -ve feed willy nilly) and/or voltage dips due to starting on near flat battery that is the cause of most issues. RTFM and follow the guide and it should be OK.

 

[Phill D]

There is a shutdown and startup procedure for battery removal which ensures ECUs are powered off and on in the correct order.
Its the uncontrolled shutdowns (pulling -ve feed willy nilly) and/or voltage dips due to starting on near flat battery that is the cause of most issues. RTFM and follow the guide and it should be OK.

The removal procedure you quote is quite correct.

whilst uncontrolled shut downs can cause the problem i do not agree it is the cause of most issues.

These ecu's can fail when you are driving at cruising speed; when the van is at idle; or even on a fully charged rested battery; most of the issues are reported by the likes of Crash data as voltage spikes, but that is only a small part of the problem but an easy excuse to keep the punter happy.
IMHO it is as a direct result of a poorly designed and constructed ECU.

 

[Jimbohorlicks]

So if I were to drive it with the ecu disconnected would I still get the airbag warning light.
I don't intend to, but it is interesting
Thanks Colin

Yes you will get an airbag light and they wont operate if you have a bump It can also turn on other warning lights temporarily..
If you buy a second hand cubit it will still require a proxy alignment .
There is someone on fun who has the kit to do that.

 

[Colino]

Once the airbag ecu is repaired, should the code be removed before reinstalling or after.
Thanks in advance
Colin