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Off Topic Airbag failure see handbook

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Off Topic Airbag failure see handbook

Both side sensors are present and Typecastboy was kind enough to give me a couple of spares to try as well.

What I really need to do is invest in MES (so I can stop bothering him for a start) and work through the issues.

My gut instinct is a cable issue since swapping the ECUs has not changed the logged fault.

I reckon a while back an honest owner had this issue and was unable to resolve it through the dealer network (the car appears to have had a good service history up until a year or so ago) ultimately it was part exchanged it or sold it on.

I think at that point it was in the hands of people who wanted to make a quick buck and rather than investigate any issue they sought to disguise it.

I know that a warning light that illuminates but fails to go out is an MOT failure, but for SRS if it fails to illuminate at all it is not a failure.

https://mattersoftesting.blog.gov.uk/common-mistakes-made-by-mot-testers/

When testing SRS MIL (Malfunction Indicator Light) lamps we are only looking to see if the lamp indicates if there is a fault with the system. If no lamp is present or it doesn’t illuminate then it can’t indicate a system fault, so it can’t be failed. Some vehicles may also incorporate warning messages on dash board displays; these are in addition to any MIL lamps and should not be used as a reason for rejection.
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So by removing the lights they managed to get it through the MOT because the warning message is not considered.

The test of the SRS warning lamp, along with a host of other items, was only introduced into the MOT test as a result of Directive 2010/48/EU. These new items were going to increase the complexity to the test at a time when the political ideal was to reduce the regulatory burden. For this reason, our remit was to include nothing additional in the test that was not required by the Directive.
As a result, an SRS MIL indicating a system malfunction was included, but as the Directive does not specify a failure for an SRS MIL being inoperative this could not be added. For the same reason, SRS checks (and other 'new' checks) do not apply to Class 3 vehicles.
However, to keep things in perspective, it must be remembered that 'SRS', as is in the name, is a supplementary rather than a primary safety system. Also we are now checking a host of items that were not previously included, so it is a step in the right direction.
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I would say time to check the wiring continuity from air bag ecu connector to side impact connectors.

Power down the airbag ecu , disconnect battery, disconnect the connector from the ecu and impact sensors , make 100% sure you are testing the correct wires (If you get this wrong you could set off the air bags with your multi meter)

Next time you have access to mes, disconnect impact sensors and see if fault code changes from intermittent to another code.

I too think faulty wire / wires / ground connection could well be underlying cause.
 
jackwhoo said:
Hello again , hope you don't mind be joining in again?
Have a look for the side impact sensors,
Maybe "crimewatch seller boi" removed or unplugged them in his quest to do as dodgy a job as possible?

Thanks for keeping us in the loop.

Jack
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We checked the sensors they are there and plugged in. The side sensors don’t seem to show up in MES.
 
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typecastboy said:
We checked the sensors they are there and plugged in. The side sensors don’t seem to show up in MES.
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Any sign the car has been lifted incorrectly, I don’t know the location or routing of these wires but it used to be a common mistake for people to cause damage to floor wiring looms by putting the jack or lift in the wrong place and crush a load of wires when the floor pan buckled. The fact that it is effecting both sides might be similarly placed lifting method, or they have a common routing before they split off to each side.
 
AndyRKett said:
Any sign the car has been lifted incorrectly, I don’t know the location or routing of these wires but it used to be a common mistake for people to cause damage to floor wiring looms by putting the jack or lift in the wrong place and crush a load of wires when the floor pan buckled. The fact that it is effecting both sides might be similarly placed lifting method, or they have a common routing before they split off to each side.
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Not at all. Loom is under the plastic kick plates that run along the base of the floor from front to back.
 
So my daughter came back to visit from Uni this week and I had the car booked into PDH cars for more investigation.

Still the same issue they could see Airbag module was there and the live values, but they could not proxi align it.

So they agreed to order a new airbag module to see if that would resolve the issue. If it did I would be given the choice of buying it or not, otherwise it would be returned to stock with no charge and they would keep investigating.

Well the new airbag module arrived yesterday it was fitted, proxi aligned and the problem was gone! WTF!

So maybe the second hand one I purchased with the same part number had the same faults as the original, but that seems like a huge conincidence.

Now here's the kicker ... the module they fitted (51918659) was not a metal cased module like the original (5186776).


So maybe the original has been superseded or is no longer available and this is a compatible replacement. Or maybe the whole problem is because the metal box module the car came with was the wrong one in the first place and this is why the second hand replacement did not work either.

Any how it's fixed the labour was just £95 but the part £479 ex vat. So a grand total of £689 to resolve.

The technician did originally suggest that I should just sell it on with a known fault, but I explained I would be happy to try a new ECU.


An expensive lesson but this is the first time in around 30 years of car ownership I have paid a garage to do anything other than put new tyres on. It's my daughter's car and so I only have limited access to it, so the way I view it is I've saved so much money servicing and maintaining cars over the years I can afford to splash out once in a while.

IMG-20200725-123236.jpg

IMG-20200725-150619.jpg
 
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chris3234 said:
My guess somebody changed to the wrong ECU after the original failed
That didn't fix it so sold the car on
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I think that could well be the case. As I said early on the car came with a plastic bodied ECU, which he said "just need to fit that and it'll fix the problem". Upon inspection you could see the ECU had been opened (plastic tabs were broken).

As an aside in the Land Rover world (Defenders, Discos) that I am more familiar with we can get copies of parts manuals (PDF or Rave software) where it is quite easy to check what part numbers are compatible with vehicle by model year or VIN number. Does such a resource exist for the Fiat 500 ... either a PDF or online style microcat resource?
 
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Aha !!

Just been on www.fiatdalys.lt put the VIN number in and the SRS module it suggests for this car is the same as the one the dealer fitted!!.

So it looks like both the one that was fitted to the car when purchased and the replacement supplied by the seller were wrong.

So that probably solves the mystery of why neither typecastboy nor the dealer could get the proxy alignment to work.

Mystery solved I think.

The mistake in the fault finding was assuming that the part fitted was correct but just defective.
 
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I just clicked on the link and got asked to install some sort of "getsafe" add-on. Second attempt went to some strange adverts search engine. I won't be trying again.
 
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varesecrazy said:
Without counting back all 4 pages..

Ive no idea what post that is

On my phone you report a post with the (!)
Icon

I seem to recall there is a red triangle on classic PC version
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Oops!

I've reported the post with the correct link. I no longer have the ability to edit eit.
 
So the latest update is that the orange warning triangle came up today.

I see there is a whole host of reasons why this can come up. My simple OBD2 reader is showing zerow faults. I will call the dealer tomorrow.
 
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