I’ve done a scan of my 500 using MES and it has come back with just 2 errors which are stopping me from doing a proxi alignment, everything else works perfectly but the errors for the Airbag ECU are as follows;

B0103 - Driver Airbag Resistance (1st Stage)
B0127 - Passenger Airbag Exclusion Control Light

I’ve tried to google the first code but the vast majority are in Italian and I was wondering if anyone here would be able to point me in the right direction, I’m looking to sell the car as I have bought a new one but I don’t want to pass it on with the airbag light illuminated.

Oh I think I know what this is. This sounds exactly like the problem Sean from the Isle of Wight had with his daughters car. We tried everything. I had the same almost identical problem with a car I had sold a few years ago and I had never been able to get to the bottom of it and had to give up.

A good thing to try. In the menu on the speedometer, scroll through and see if you can turn on or off the passenger airbag. If either when you turn it off and confirm it, it still stays on or vice versa or the passenger airbag doesn't even appear in the menu, which is the most likely. I think I can say with almost certainty that surprisingly, the culprit is the speedometer itself. Sean sent his away to be repaired when it had the lights that show up when the indicator is on and when he got it back it was doing this. He tried new ECU, exactly the same.


I had an old speedo that I sent him in the post, and although the display in the middle didn't work, all of his airbag lights went out. He then sent the speedo back to those that repaired it. or someone else I can't remember exactly. They repaired it again, sent it back and all was good.

Personally I would have just replaced the speedo as it's cheaper. You have MES so you can increase the mileage if you get a new speedo with a lower mileage than your car and do a proxi alignment.

My money is definately on this. It seems to be becoming a more regular fault. The symptoms are always the same.

You’re right I just tried to toggle the passenger airbag from ‘off’ to ‘on’ and it didn’t make any difference it just stayed off, would a faulty speedo really cause the airbag fault message on startup too?

How difficult is it to remove the speedo and how will I know another speedo will definitely work from a similar 500?

FabiaVRSBlue said:

You’re right I just tried to toggle the passenger airbag from ‘off’ to ‘on’

how will I know another speedo will definitely work from a similar 500?

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Good news

Look at their post history

FabiaVRSBlue said:

You’re right I just tried to toggle the passenger airbag from ‘off’ to ‘on’ and it didn’t make any difference it just stayed off, would a faulty speedo really cause the airbag fault message on startup too?

How difficult is it to remove the speedo and how will I know another speedo will definitely work from a similar 500?

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The Speedo enables and disables the passenger side airbag for a child seat
So the airbag CAN line must connect to it
I assume it doesn't send the correct signal to the airbags ECU
Hence why it throws the warning light up

FabiaVRSBlue said:

You’re right I just tried to toggle the passenger airbag from ‘off’ to ‘on’ and it didn’t make any difference it just stayed off, would a faulty speedo really cause the airbag fault message on startup too?



How difficult is it to remove the speedo and how will I know another speedo will definitely work from a similar 500?

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Well you won’t for definite. Takes about half an hour to change a speedo. Top and bottom cowlings off, speedo bezel off and then a few screws. I would suggest you bite the bullet and get one and try it. If it isn’t that, you can always sell it. Just make sure you get a speedo with a lower mileage than your car.

typecastboy said:

Well you won’t for definite. Takes about half an hour to change a speedo. Top and bottom cowlings off, speedo bezel off and then a few screws. I would suggest you bite the bullet and get one and try it. If it isn’t that, you can always sell it. Just make sure you get a speedo with a lower mileage than your car.

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No problem I’ll give one a bash, are they all pretty much the same the instrument clusters? Mines a 2012 so I’m assuming a 2012-2017 model one will work fine? Only reason is because a lot of them say to check VIN numbers before purchasing?

You won't need to check VIN numbers. The earlier models up to about 2010 have a different one which doesn't incorporate the facility for the stop/start, so make sure you get a slightly later one. You also need to make sure you get a pre-facelift one.

Anything from 2011-2015 should be fine. You could upgrade to a funky colour one, but again needs to be from a pre-facelift car.

They are plug and play but will most likely need a proxi alignment. Sometimes they do, sometimes they don't but you have MES so you can do that.

The earlier ones that you should avoid have the time in a a really big font.

typecastboy said:

You won't need to check VIN numbers. The earlier models up to about 2010 have a different one which doesn't incorporate the facility for the stop/start, so make sure you get a slightly later one. You also need to make sure you get a pre-facelift one.

Anything from 2011-2015 should be fine. You could upgrade to a funky colour one, but again needs to be from a pre-facelift car.

They are plug and play but will most likely need a proxi alignment. Sometimes they do, sometimes they don't but you have MES so you can do that.

The earlier ones that you should avoid have the time in a a really big font.

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I’ve just bought one that is listed as 2012-onward however I’ve just noticed on the rear when I zoomed in on the sticker there’s a date label of 2017... will this be an issue? The unit itself looks identical.

It's usually only an issue on the colour ones but hopefully it should be OK. It will certainly show you whether it has cured the problem.

typecastboy said:

It's usually only an issue on the colour ones but hopefully it should be OK. It will certainly show you whether it has cured the problem.

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I’ve forewarned the guy I bought it from that it may not be compatible and he said the same and we agreed if it doesn’t work I can send it back for a full refund so no harm in trying, fingers crossed for the next couple of days!

Well after crossing my fingers for a couple of days it turns out it’s not the Speedo’s fault after fitting the new one the airbag message and light remains, looks like I’ll have to get the thing booked into a garage that can do airbag ecu work and hopefully they find out what’s wrong, if anyone knows anywhere within Kent that can do this sort of thing?

What year is your car as is the Speedo was a 2017 year one it would only work in post 2015 cars

chris3234 said:

What year is your car as is the Speedo was a 2017 year one it would only work in post 2015 cars

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It’s a 2012 lounge, do you really think a pre-2015 speedo would make a difference to the Airbag fault light showing up?

Get your ECU out and get the code number then look on eBay for the same number. I’m so surprised the speedo didn’t sort it.

What’s MES showing?

I thought the airbag control was moved to the radio on the 2015 cars rather then the Speedo?

typecastboy said:

Get your ECU out and get the code number then look on eBay for the same number. I’m so surprised the speedo didn’t sort it.

What’s MES showing?

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Do you mean the main ECU or the airbag ECU?

I also tried to re-enable the passenger airbag using the Speedo’s menu but it was also doing the same thing as my original it just goes back to “off” when I try to turn it on however the passenger airbag light on this new cluster doesn’t light up which is odd.

the passenger airbag light on this new cluster doesn’t light up which is odd.[/QUOTE]
Almost as if its an incompatible unit..

Did you say you had an understanding with it seller to return it ?

varesecrazy said:

the passenger airbag light on this new cluster doesn’t light up which is odd. Almost as if its an incompatible unit..

Did you say you had an understanding with it seller to return it ?

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Yup I’ve arranged to have it sent back, I’ve found a couple other earlier speedos though one is for LHD, would that work or is there differences?