Member Since: 21 Sep 2015
Location: Bodmin
Posts: 32
Wires under passenger seat
I've started getting a "B0072-1B - Passenger's safety belt pretensioner deployment control - General electrical failure - circuit resistance above threshold".
I've taken the front cover off and checking the connectors, and I've noticed what looks like an alteration to the wiring wrapped in blue tape, as in the photo. Is that from factory, or is it something a previous owner has done?
Click image to enlarge
Before anyone mentions it, I'm also checking the TSB LA501-025 about the routing of the wiring.
28th Sep 2024 11:19 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10674
not sure. The wires look too thick to be airbag related.
It's the orange and yellow connectors you need to worry about.
I think yellow is airbag
and orange pretensioner
but not sure. Blue is on my mine for some reason. Seatbelt buckle?
28th Sep 2024 3:28 pm
SpikeUK
Member Since: 21 Sep 2015
Location: Bodmin
Posts: 32
That's handy to know, so hopefully I can measure the resistance across the pretensioner on the orange connector
28th Sep 2024 6:09 pm
SpikeUK
Member Since: 21 Sep 2015
Location: Bodmin
Posts: 32
Does anyone know how the internal wiring works on these seat belt pre-tensioners? The pre-tensioner I'm dealing with here has two plugs, orange and blue. I think I am correct in that the orange one is the actual pre-tensioner, and the blue is the buckle latch so the computer knows the seat belt is latched.
I understand the resistance across the two pins in the orange connector should be in the range of 3 to 4 ohms for a good firing mechanism. I am getting around 0.5 ohms. I've got what I hope is a good 2nd hand replacement, and that also gives 0.5 ohms on the pins in the orange connector.
I also tried the blue connector, I thought that was probably just a make / break connection for the computer. With the seat belt unlatched, I put the meter across the two pins in the blue connector and it gave me open circuit. I then latched the seat belt, but the meter remained at open circuit - which I thought was very strange. My 2nd hand replacement is almost exactly the same, except it gave 28M Ohms which is almost open circuit.
So nothing is making sense here, can anyone make sense of it?
A few photos of how I tested:
Original mechanism Orange connector:
Click image to enlarge
Original mechanism, Blue connector, Unlatched:
Click image to enlarge
Original mechanism, Blue connector, Latched:
Click image to enlarge
Replacement mechanism, Orange connector:
Click image to enlarge
Replacement mechanism, Blue connector, Unlatched:
Click image to enlarge
Replacement mechanism, Blue connector, Latched:
Click image to enlarge
And after all that, unrelated to the above but visible in the photos, can anyone see my very annoying mistake....
2nd Oct 2024 4:58 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10674
Is your meter battery low!?
With airbag connectors, when unplugged there is usually a bridging mechanism to short the 2 contacts out. That’s probably why your getting 0.5R
2nd Oct 2024 5:06 pm
Doughboy
Member Since: 04 Aug 2020
Location: Tamworth
Posts: 93
sorry to jump on thread, im getting an airbag fault flag up... only when a passenger is sat on the seat and i hit a bump or go round a corner.. can i reseat these connectors with battery still on or do i need to disconnect then try. im not convinced it is these connectors but maybe something going on with the seat sensor.. i dont know. my live data is always showing a current but high resistance as opposed to full open circuit. any help appreciated
Rich
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