Technical Airbag failure :(

[wedders]

Hi all.

My poor old Idea (2004, 1.4 petrol) started showing "Airbag Failure" a couple of months ago along with the dash light and some upset beeps.

I've been trying to get a fault code with various scanners. I have an ELM clone and MES vehicle list says basically everything in this car can be read by ELM, so I've been trying that... I can connect to the engine, ABS, steering, but not to the airbag.

(I also saw service interval reset which made me happy as that's needed doing for ages, but that also wont connect )

Anyway, nothing is giving me any fault codes.

I did physically access the airbag ECU and disconnected and reconnected all the cables at one point and that stopped the error for a single journey before it came back.

I'm now thinking the problem might be between the airbag ECU and the rest of the CAN network, or perhaps the airbag ECU is not getting power at all?

I will go and attack the connectors better tomorrow but wanted to query if anyone had any knowledge that might help!

 

[bugsymike]

Hi all.

My poor old Idea (2004, 1.4 petrol) started showing "Airbag Failure" a couple of months ago along with the dash light and some upset beeps.

I've been trying to get a fault code with various scanners. I have an ELM clone and MES vehicle list says basically everything in this car can be read by ELM, so I've been trying that... I can connect to the engine, ABS, steering, but not to the airbag.

(I also saw service interval reset which made me happy as that's needed doing for ages, but that also wont connect )

Anyway, nothing is giving me any fault codes.

I did physically access the airbag ECU and disconnected and reconnected all the cables at one point and that stopped the error for a single journey before it came back.

I'm now thinking the problem might be between the airbag ECU and the rest of the CAN network, or perhaps the airbag ECU is not getting power at all?

I will go and attack the connectors better tomorrow but wanted to query if anyone had any knowledge that might help!

You need to get the error codes read correctly first.
What ever you do don't short out or bridge any connectors.
The previous owner of my daughters Punto Evo tried to repair a passenger seat occupancy sensor and ended up destroying the Body Computer (BCM) trying to fix an ABS fault.

 

[varesecrazy]

Hi all.

My poor old Idea (2004, 1.4 petrol) started showing "Airbag Failure" a couple of months ago along with the dash light and some upset beeps.

I've been trying to get a fault code with various scanners. I have an ELM clone and MES vehicle list says basically everything in this car can be read by ELM, so I've been trying that... I can connect to the engine, ABS, steering, but not to the airbag.

(I also saw service interval reset which made me happy as that's needed doing for ages, but that also wont connect )

Anyway, nothing is giving me any fault codes.

I did physically access the airbag ECU and disconnected and reconnected all the cables at one point and that stopped the error for a single journey before it came back.

I'm now thinking the problem might be between the airbag ECU and the rest of the CAN network, or perhaps the airbag ECU is not getting power at all?

I will go and attack the connectors better tomorrow but wanted to query if anyone had any knowledge that might help!

My old Idea that you probably read the OBD access GUIDE on..

Had a similar niggle for years.. A poor connection somewhere

Again that wouldn't communicate properly..

Mots were OK.. Because it was intermittent

Does yours Chime on and off as you drive.. Or just Fails as you start a journey?

 

[wedders]

You need to get the error codes read correctly first.
What ever you do don't short out or bridge any connectors.
The previous owner of my daughters Punto Evo tried to repair a passenger seat occupancy sensor and ended up destroying the Body Computer (BCM) trying to fix an ABS fault.

I have no intention of doing any "heavy lifting" beyond cleaning connectors without knowing what the problem is! Especially on a system that could literally blow up in my face

But if it is a connection problem between the airbag controller and the rest of the car, there is no fault to read beyond "mate where's your airbags"

My old Idea that you probably read the OBD access GUIDE on..

Had a similar niggle for years.. A poor connection somewhere

Again that wouldn't communicate properly..

Mots were OK.. Because it was intermittent

Does yours Chime on and off as you drive.. Or just Fails as you start a journey?

A few seconds after ignition it beeps and the screen starts showing "Airbag failure", it beeps once more 30s later, but the screen continues showing "Airbag failure. Switch off engine"

I'm not sure what you mean by your OBD access guide, I'm just going by the vehicle support list on MES. If you've got a link to some more info that would be great (have done some searches here but can't see anything)

 

[varesecrazy]

I have no intention of doing any "heavy lifting" beyond cleaning connectors without knowing what the problem is! Especially on a system that could literally blow up in my face

But if it is a connection problem between the airbag controller and the rest of the car, there is no fault to read beyond "mate where's your airbags"


A few seconds after ignition it beeps and the screen starts showing "Airbag failure", it beeps once more 30s later, but the screen continues showing "Airbag failure. Switch off engine"

I'm not sure what you mean by your OBD access guide, I'm just going by the vehicle support list on MES. If you've got a link to some more info that would be great (have done some searches here but can't see anything)

Mine was a dodgy connection "somewhere"

It was crash repaired.. So could have been anywhere

Fault code reading - Idea - socket location + access

the dash panel in our sample 55 reg Eleganza is secured by; 3 philips self-tapper screws along the top edge( clearly visible ) one self-tapper that is tucked down the LH lower edge ( door pillar) once the screws are removed the panel is still...

www.fiatforum.com

 

[wedders]

Hijacking my own thread with more problems...

Out on a test drive and car throws some more electrical gremlins. Really putting me through the ringer this year!

Temperature shot to max and the engine juddered for a moment. ECU showed codes P0115 and P1866.

I've had all this before although not both codes together, and the temp sensor was opposite before (i.e, it went below minimum rather than to max).

I pulled over and checked under the hood just in case. Had trouble restarting it (see below) but eventually did, let it idle for 10-15m, then pulled away and completed my journey with no problems and working temp gauge.

Now when I put the key in MAR the temp shoots to max and the car beeps it's annoyance, then it goes to normal for 10-20 seconds, then back to max for a few seconds and beeps etc etc. If I try to start the engine it cranks, but the temp gauge maxes and I assume it's choosing to not start the engine.

Any and all advice on what I should be checking welcome! Relevant eLearn diagrams attached...

I went out with my multimeter today and checked

• the temp sensor (K036, reading 3.75 kohms, a-ok)
• continuity from temp sensor to the 60 pin ECU connector (M010B) while wiggling the cable about (a-ok, read the same resistance across the sensor from the connector)
• continuity between the timing sensor (K047) and the ECU connector, and the temp sensor since one pin is directly connected
• continuity between the MAP sensor (K043) and the ECU connector as I've previously changed that trying to fix P1688

I was also trying to find all the earth points, but the eLearn diagrams are a bit wonky.

• I couldn't find C040 (in red), but there was a ground coming out of the M010 wire bundles and attached to the corner of M010 (in yellow) - is that it? Other docs refer to that as M010C. Cleaned it up anyway.
• Cleaned up C010 on the front of the car.
• I'm guessing C012 is in the wheel well, only accessible by removing the wheel?

 

[varesecrazy]

Have you replaced the main Battery to Chassis to Engine cable?

 

[wedders]

Nope I have not - is that a common issue?

That would presumably involve C040, the engine ground, which I couldn't see

 

[wedders]

Pulled out the battery-body-engine earth cable today and will replace - not sure how I missed it yesterday, had battery tray out and everything.

Looks ok, but I can see some corrosion on exposed copper where the body lug is. It certainly hasn't been replaced in the 10 years I've owned the car.

I'm still not sure where C40A "earth on engine" is, as this cable is described seperately on eLearn (C1 = battery earth, C2 = "battery earth on engine" C3 = "battery earth on bodyshell")

 

[wedders]

Main earth replaced, initally seemed to help but issue remains.

Turning on ignition I don't always immediately get over temp, nor are they at such regular intervals, but it does still do it.

For science I took a jumper cable and connected the ground on the engine ECU to a bolt on the top of the engine - simulating C40 that I can't find - and have not had a single overtemp while that cable was in place. Fault disappears and reappears when you add/remove the connection.

I guess I need to find C40, or run a new cable from the top of the engine. Didn't try to start the engine with the jumper, but if it does fire up then that must be the problem???

---

Also finally got a read on the airbag - crappy ELM clones!

• B100F - passenger side airbag resistance (7 ohms)
• B1001 - control unit faulty

I can of course check the wiring to the airbag in question, but is the B1001 going to need a replacement control unit?

 

[The Panda Nut]

I feel a bad connection somewhere is far more likely than the control unit. Unless this has been bashed or soaked it has no reason to fail. Alow deterioration of connections is common. I always suspect under seat connections in this respect.

 

[bugsymike]

No guarantee that is the case here , but it was the initial fault on daughters 2012 Punto Evo, it was only the poor repair that killed the BCM as there should be a resister in the circuit to prevent damage and give correct readings.

 

[varesecrazy]

No guarantee that is the case here , but it was the initial fault on daughters 2012 Punto Evo, it was only the poor repair that killed the BCM as there should be a resister in the circuit to prevent damage and give correct readings.

The Puntos.. So probably 95% same as your idea... had an Earth cable up around the throttle body..

Sounds like you basically added your own?

 

[wedders]

Thanks all, here's result of today's wrenching...

ELECTRICAL:

• Went digging for C40, removed ECU and throttle body and starting feeling along the cable bundle behind the engine.
• Eventually found it - I think. Back of the engine, pretty much in line with the throttle body, tucked underneath some component related to the climate control system (it's labelled "Denso" so I'm assuming). You can't really see the connection from above or below, but you can see an unthreaded hole, and the ground bolt is a little above that. I shoved my phone down there and took some pictures in case it helps anyone in future.
• 
  
• Tested with multimeter and wiring seemed ok, cleaned as best I could and re-attached.
• Car still showing overtemp intermittently.
• SO I used half of the old battery-body-engine ground cable and put that between the engine ECU ground point (M10C) and a bracket that holds a connector on the top of the engine, roughly what I was doing with a jumper cable (image attached).
• With ignition on everything seems fine. Again did not try to start the engine as light was fading, so I quickly had a look at airbag...

AIRBAG:

• Fiddled with passenger seat connector and that airbag is now reading at 2 ohms!
• Passenger airbag fault cleared with no problems.
• B1001 error remains
• Anyone had experience of people like crashdata or northern auto who offer repair services?

 

[bugsymike]

Re the B1001 error code "proxi alignment " could well sort that, if you have suitable diagnostic tool.

 

[wedders]

Thanks bugsy - gave it a go today and hasn't made any difference. It did make some changes but the only thing highlighted was radio/nav, guess it was never proxid after the aftermarket one was installed. Airbag showing as active/ok. When I open proxi now it says everything is configured correctly.

It did error trying to program the dashboard? But wrote to body and climate control successfully.

Have removed airbag controller and contacted crashdata to see if they can work on it.

I've seen online people fixing this by reflashing the microcontroller - I have the necessary equipment, but not sure how to open the unit and scared to force anything and definitely ruin it

--

Did start the engine today for the first time in a couple weeks! MOT is gone so I can't move it, but ran and revved for a bit and all seems well.

Had a P1866 stored but didn't come back when I cleared it, and no temp gauge shenanigans.

Hoping that's the end of that nightmare (though I might try to properly replace that ground at some point).

 

[wedders]

Hi again everyone.

I did end up opening the airbag controller and reprogramming the memory inside to remove the fault code. Big props to the Digital Kaos forums where there are some brilliant people who will take a copy of the memory in a controller and clear it for you either with an expensive professional software tool or by hand.



I can understand people being a bit squeamish about fiddling with the airbag system but a new unit would probably cost more than the car, so this was a good solve for me!

For anyone interested I've written it up a bit on my blog.