Technical Start/stop unavailable, airbag failure and electrical problems

[Maru2604]

I bought a 1.2 Pop last week that is Cat C. It drives fine but I'm having the following issues with it:

Airbag failure, see handbook

I've read up about this but I'm not sure if messing with the sensors under the seat would deploy the airbag? I understand I'd need to disconnect the battery to do this but what are the chances of it deploying once I reconnect the battery?

Start/Stop unavailable

It shows this all the time, start/stop has never worked and only kicks the engine on if the engine is stalled.

Electrical misc??

The dash screen doesn't come on if the car has been sat for a while. Sometimes it won't come up until I've driven for a bit and then when I restart it comes on. Other times it will actually come on the 2nd try but if the car has been sat for a while it will very rarely come on the first try.

I've made a dropbox folder with some images of what's going on as well as a video that shows the screen flickering I'm thinking battery issues but I'm not sure.

Can anyone advise on what all this is and how much it should cost to get it sorted out? Can I do any of this myself?

 

[typecastboy]

All of those could simply be the battery, so it’s worth bench charging over night. If it still does it, invest in a new battery. However as you have bought a Cat C it’s possible that whoever repaired it has not replaced the airbag ECU. You could do with plugging it in to MES, that will tell you which airbag is causing the light to come on.

Don’t mess with any airbag wires until you have disconnected the battery. Only an accident or an inadvertent static charge in you when messing with airbags with the battery connected would cause a bag to blow. It’s perfectly safe to do it with the battery disconnected. You mention the wires under the seat, they are for the seat airbag and passenger sensors for the seatbelt. What makes you think the seats are the culprits.

If you don’t know anyone with MES it’s worth investing in it, it will tell you the problem. What’s your location, maybe someone near you can help.

 

[Maru2604]

Thank you so much for all that info. I don't have a battery charger but I have a multimeter so I can check resting, startup and idling voltage. Will that help at all? I have a Halfords near me and can book in a free battery check too, that any good?

Not sure what MES is, I tried googling but couldn't find anything? Is it like an advanced OBD2 reader?

I'm based in Enfield, North London.

I mentioned the wires under the seat because I read about it on this forum. I can't attach the URL because I'm a new user but if you paste this into Google it'll find it.

/500/295179-airbag-light-control-unit-3.html

 

[chris3234]

Mes is multiecuscan
Basically a version of the dealership diagnostic software that available to the public it can get much more detailed codes from the car rather then basic codes e.g passenger airbag

 

[Bluetruck]

Typecastboy is on the money. The airbag ECU is finished unfortunately and needs replacing. Its located under the heater box but is dead easy to change. The car will then need all the codes deleting and a Proxy Alignment. Unfortunately the ECU is a bloody fortune from Fiat.......

 

[typecastboy]

Typecastboy is on the money. The airbag ECU is finished unfortunately and needs replacing. Its located under the heater box but is dead easy to change. The car will then need all the codes deleting and a Proxy Alignment. Unfortunately the ECU is a bloody fortune from Fiat.......

But you can buy good ones on eBay for around £50-70.

 

[typecastboy]

3 x 10mm bolts and it’s off.

 

[typecastboy]

If you fancy a drive down to Orpington in Bromley, I’ll plug MES in and see what we can do.

 

[Maru2604]

Thank you everyone! I changed the battery as I had a test done in Halfords. It was reading 224A and it's rated at 450A!

All the issues with the screen not coming on, the jumbled up words and start/stop have now been sorted.

However the airbag failure is persisting, so I believe it is the either the connectors or the airbag ECU. How much should a garage charge for proxy alignment?

I can replace the airbag ecu and clear the codes myself.

Also any tips on where to find one cheap? eBay is quite expensive right now at £130+!

 

[typecastboy]

Just keep looking on eBay until you find one cheaper. They come up all the time. Proxy alignment is £25 plus VAT I believe, or free from someone with MES.

If you replace the ECU you won’t need to clear the codes as they’ll be gone.

 

[Texas149]

Try and look for " Fiat 500 Breaking for Spares" as opposed to just looking for the ECU as you might get a better result ( cheaper!)

Paul m.

 

[chris3234]

Try and look for " Fiat 500 Breaking for Spares" as opposed to just looking for the ECU as you might get a better result ( cheaper!)

Paul m.

Just make sure you buy one from a car that hasn't had an airbag go off

 

[typecastboy]

I’ve bought ecus from this seller. He has this one for £75

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/323179582881

 

[jnoiles]

Get a copy of this and a cable, plug it into the OBDII port and read off the errors. See if you can get anymore information from it: http://www.multiecuscan.net

Re the airbag, I've unplugged and reconnected the seat connectors tons of times without issue but obviously, use care and at your own risk. The underseat connectors can wiggle loose if they've been fiddled with. Check the connectors to see if any tabs are broken or pins corroded.

Re the dash, not sure. That's a new one to me.

 

[Maru2604]

So unfortunately the start/stop issue came back (to an even worse state, now it doesn't work at all and always shows the yellow start stop light) after a few days with the new battery. I thought something was draining the battery so went back to Halfords for the free battery check and it's absolutely fine.

The display keeps doing crazy stuff, it showed the sport light even though the car doesn't have sport mode and generally just does all kinds of weird things.

 

[chris3234]

Earth problem?

Check the fuse box for any water ingress or corrosion

 

[typecastboy]

The stop start light means it’s turned off. You really need MES to diagnose the problem.

 

[Maru2604]

START/STOP:

Soo.. funny thing. Turns out the brake lights were always on. Only one person told me on a journey from London to Canterbury and back!!

Once I adjusted the brake lights switch, start/stop started working as normal.

AIRBAG:

But my airbag light has now come back :bang: (after 5 days or so) which means whatever the garage did to it (clearing the codes I'm guessing?) didn't work. Does this confirm the airbag ECU failure? I see one on eBay for £99.. how do I go about fitting one? Is it hard?

DASH:

With the dash.. it's now completely off and hasn't turned on for 2+ days. Back when it was jumbling up letters, if I hit it - it would change what it's showing so I'm gonna try and take it apart and use electrical cleaner on the connections. Praying that will sort it out - otherwise it will need a new dash

 

[Craigio]

when you say you adjusted the brake light switch, can add some detail on what you did - I have the same start stop issue

 

[Maru2604]

when you say you adjusted the brake light switch, can add some detail on what you did - I have the same start stop issue

Ok so - go to your passenger footwell area with a flashlight and get someone to press the brake.

It'll look like this

You need to adjust the white pin (the one that goes in and out) with some pliers (I put tape on mine cause they're quite rough and I didn't want to cause unnecessary damage)

It has "clicks" which it adjusts to. By looking at the pin while someone is pressing/letting go of the brake pedal, you will understand whether your switch needs pulling out or pushing in.