Technical Connection between failure lamp and ecu

[KRaikkonenNo1]

Hi, haven't posted for a couple months, have been away and not had time to go online much.

Anyway, both of my airbag lights are illuminated and will not go out even with mes. I will attach the pictures I took before of the problem and see if anyone can shed any light.

Thanks!

 

[oXRUSSXo]

Hi, haven't posted for a couple months, have been away and not had time to go online much.

Anyway, both of my airbag lights are illuminated and will not go out even with mes. I will attach the pictures I took before of the problem and see if anyone can shed any light.

Thanks!

Dont know how you can resolve it but from the sound of it the ecu cannot connect to the module that controls the airbag lights. Could be that the plug that goes into the back of the cluster isnt pushed in tight or the cluster has become faulty.

First i would take the cluster out and check its plugged in tight. Maybe have a spray of electrical cleaner on the connections.

If no luck i would try a replacement cluster.

Thats all i can think of. Ive never seen that issue before

 

[MikeSalt]

My interpretation of that is that the actual MIL lamp has failed. Are you a reletively new owner to this car? I wonder if someone has deliberately tampered with the MIL to hide a fault. When you start the car, does the MIL come on with all the other lights, then disappear soon after the engine is started?

 

[KRaikkonenNo1]

My interpretation of that is that the actual MIL lamp has failed. Are you a reletively new owner to this car? I wonder if someone has deliberately tampered with the MIL to hide a fault. When you start the car, does the MIL come on with all the other lights, then disappear soon after the engine is started?

I've had the car over a year now and have had the dash out numerous times. Few months back I changed all the smd behind the dash, do you think this could cause any issue like this?

The eml and airbag lights come on, and is currently staying on because of another problem. And the 2 airbag lights stay on.

When I first removed the dash about a year ago, there was some foam over the gap for the airbag lights. But it has been fine up until recently.

Thanks.

 

[MikeSalt]

Ah yes, surface-mount diodes (SMDs) will present a completely different load to the ECU than expected from the filament bulb MIL, so the ECU will think the bulb is faulty. Probably best to change that particular bulb back to the old filament one.

 

[KRaikkonenNo1]

Ah yes, surface-mount diodes (SMDs) will present a completely different load to the ECU than expected from the filament bulb MIL, so the ECU will think the bulb is faulty. Probably best to change that particular bulb back to the old filament one.

Ohh I didn't realise, I thought the originals were SMDs also? I will swap them out on that particular bulb then and see if that fixes the issue.

Cheers!

 

[Ziggy122]

Smd stands for surface mounted diode

But as I understand there are differnet wattages and what not

I'd also see if there is 1 wire airbag ecu to dash to check there isnt a break there


Ziggy

 

[AndyRKett]

The lights are on and working which means there is a connection however my suspicion is that for the airbag module to know there is a fault in the connection it needs some way of feeding that info back, either open circuit or there is a reverse current feeding power back into the airbag ecu. And is also what it likely keeping the lights on, especially if the lights are not flashing when you start the car just always on as soon as you turn the key.

So dodgy earth/live or maybe one of the SMDs you replaced is in the wrong way round

 

[KRaikkonenNo1]

The lights are on and working which means there is a connection however my suspicion is that for the airbag module to know there is a fault in the connection it needs some way of feeding that info back, either open circuit or there is a reverse current feeding power back into the airbag ecu. And is also what it likely keeping the lights on, especially if the lights are not flashing when you start the car just always on as soon as you turn the key.

So dodgy earth/live or maybe one of the SMDs you replaced is in the wrong way round

The SMD's are polarity conscious and from what I'm aware dont work at all when the wrong way.

I replaced all the SMD's maybe 5-6 months ago, maybe longer but this problem only started (the 2 airbag lights flashing and illuminating), 2 months ago. So they were fine for some period which makes me think there may be an actual issue like you mention.

Regarding your last sentence, I actually think the airbag lights or at least one of them does flash, I will double check this later.

Where would you suggest to start looking?

Thanks.

 

[AndyRKett]

an led/SMD is a diode so the electrical equivalent of a non return valve, power only flows one way (up to a point)

Now if you installed very cheap SMD it's quite possible over time they have broken down and are burning out which tends to see them acting like a resistor. All the bulbs in the instrument panel share the same ground so one faulty SMD/LED could be pulling an unusual current and the only ecu that's going to see that is the airbag ecu

 

[KRaikkonenNo1]

an led/SMD is a diode so the electrical equivalent of a non return valve, power only flows one way (up to a point)

Now if you installed very cheap SMD it's quite possible over time they have broken down and are burning out which tends to see them acting like a resistor. All the bulbs in the instrument panel share the same ground so one faulty SMD/LED could be pulling an unusual current and the only ecu that's going to see that is the airbag ecu

Can confirm that the red airbag light is continuously on and the orange (passenger one I think) is constantly flashing.

The majority of the SMD's I bought were good quality ones from crazyleds, apart from a few red ones as they were out of stock so I had to resort to eBay.

I will get the cluster out and resolder them with a few new SMD's.

 

[AndyRKett]

Can confirm that the red airbag light is continuously on and the orange (passenger one I think) is constantly flashing.

The majority of the SMD's I bought were good quality ones from crazyleds, apart from a few red ones as they were out of stock so I had to resort to eBay.

I will get the cluster out and resolder them with a few new SMD's.

I'm not guaranteeing that its the SMDs but now you've said the airbag light is constantly on it does sound like an possible ground leak type problem somewhere

When you take the cluster apart examin the tracks very carefully for anything that's burnt or large solder blobs that might be shorting

 

[Ziggy122]

This may help here

There is 1 wire that runs from the airbag warning light in the dash to the Airbag ecu




A5 - instrument pannel
A137 - airbag module
H98 - Airbag warning light
H117 - Passenger exclusion switch

Ziggy

 

[KRaikkonenNo1]

Little update. I took out the cluster today and removed the suspect airbag SMD's which were still fully working and in tact. Circuit tracks looked "ok" but slight marks.

Re soldered with new SMD's, put back in car but airbag lights were still on. So switched on MES, in an attempt to clear the code again and voila the code cleared and has so far stayed off! (bearing in mind that whenever I have attempted to clear the code before it would not even try).

Soo something must have changed....but now have led error on my dash display which I think is the handbrake light not illuminating.

Everytime i fix one dodgy led/smd, another on at least ALWAYS goes.

 

[Ziggy122]

Little update. I took out the cluster today and removed the suspect airbag SMD's which were still fully working and in tact. Circuit tracks looked "ok" but slight marks.

Re soldered with new SMD's, put back in car but airbag lights were still on. So switched on MES, in an attempt to clear the code again and voila the code cleared and has so far stayed off! (bearing in mind that whenever I have attempted to clear the code before it would not even try).

Soo something must have changed....but now have led error on my dash display which I think is the handbrake light not illuminating.

Everytime i fix one dodgy led/smd, another on at least ALWAYS goes.

LED fail is as you said - an icon is failing to work

You may find that working on 1 SMD the heat/been distrubted blows the next

I had this on a picasso using standard little 1.2w bulbs

you replaced one - another 1 blew, replaced the blown - another 2 blew
Replaced those 2, another one blew

In the end i said **** it - replaced every single one for new = No issues

Ziggy