Had a young lad drop by this evening with an airbag light on.
His 3.0i had a parasitic drain which the auto-electrician traced and fixed, but also noticed a bit of tape stuck over the airbag light.
So I tried my Autophix, INPA and Scanner 1.4. None could even see any of the airbag modules. Very odd.
Guessing that the satellite modules feed back through the centre SIM85 I prised out the coin holder behind the handbrake so I could see it.
Quickly became obvious what the problem was:


The wire had been cut and the end taped up, so not an accident.
That wire is red and white striped with a yellow tracer round it. A quick look at NewTIS proved it to be the K-Bus circuit.
For those who don't know, the K-Bus is a kind of ring main that connects all the control modules. If one module fails then it can cause weird things to happen elsewhere. Examples I've seen include indicators working but no light on the dash, wipers working randomly, and even one car where you could only wind the windows up or down with the doors open!
I have a sneaking suspicion that the SIM85 failed and caused all sorts of issues. Rather than pay to get it fixed someone has snipped the wire to isolate it from the K-Bus, to get everything else working. Then a bit of tape over the airbag light and sell it on fast.
No time to fix tonight and the lad is off on holiday in the morning, so we'll tackle it next week. Step one is splice that wire back together. Then we'll see what oddities occur. I have a couple of compatible modules and fingers crossed it will be as easy as fitting one of those.
So this lad has been driving around in a car with no working airbags!
Some people have no morals!
His 3.0i had a parasitic drain which the auto-electrician traced and fixed, but also noticed a bit of tape stuck over the airbag light.
So I tried my Autophix, INPA and Scanner 1.4. None could even see any of the airbag modules. Very odd.
Guessing that the satellite modules feed back through the centre SIM85 I prised out the coin holder behind the handbrake so I could see it.
Quickly became obvious what the problem was:


The wire had been cut and the end taped up, so not an accident.
That wire is red and white striped with a yellow tracer round it. A quick look at NewTIS proved it to be the K-Bus circuit.
For those who don't know, the K-Bus is a kind of ring main that connects all the control modules. If one module fails then it can cause weird things to happen elsewhere. Examples I've seen include indicators working but no light on the dash, wipers working randomly, and even one car where you could only wind the windows up or down with the doors open!
I have a sneaking suspicion that the SIM85 failed and caused all sorts of issues. Rather than pay to get it fixed someone has snipped the wire to isolate it from the K-Bus, to get everything else working. Then a bit of tape over the airbag light and sell it on fast.
No time to fix tonight and the lad is off on holiday in the morning, so we'll tackle it next week. Step one is splice that wire back together. Then we'll see what oddities occur. I have a couple of compatible modules and fingers crossed it will be as easy as fitting one of those.
So this lad has been driving around in a car with no working airbags!
Some people have no morals!
