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Post by studabear on Nov 10, 2023 15:15:33 GMT 1
Hi lads, got my mates fiesta with me while he goes to Thailand for 6 months. Going to be working my way through a few things that need fixing while he is away.
2nd on the list is the SRS light has been a problem for a long time, light flashes and stays on. Problem does go away when its really cold in winter which happens to be when the MOT is due.
I've scanned it today using Forscan and have 1x dtc which is,
B1934 Air Bag Driver Inflator Circuit Resistance Low on Squib
I'm presuming that this is some sort of connection issue due to the fact it rectifys itself in tempratures around freezing point where I guess a connection pulls a touch tighter?
Any ideas where I want to start having a look? Disconnect battery and then remove airbag and clean connections with contact cleaner?
Thanks.
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Post by OldGit on Nov 10, 2023 19:48:26 GMT 1
Most likely the 'clock spring', the contacts are gold plated and don't really get tarnished / corroded as such. The test procedure is disconnect battery, remove drivers frontal airbag, disconnect SRS module, connect decade box (or known small value resistor ~2Ohms) to connector at SRS module, connect Ohm meter to steering wheel contacts and check resistance, rotate wheel and see if resistance changes / spikes. DON'T connect Ohm meter at SRS module end - if you get the wrong pins you could activate a squib, with the meter at the 'consumer' end, and the resistor in the wrong contacts, nothing will go badly wrong.
If the resistance is consistent but low, connect the meter to the harness on the other side of the clock spring, if that's still low, then meter end to ground on each leg from the module to the clock spring. It's possible there is corrosion in one of the wires and the cold/damp is letting a bit of moisture in and allowing contact to ground
ETA - low resistance on these circuits is unusual, they usually fail high.
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Post by studabear on Nov 10, 2023 19:56:30 GMT 1
I'm not gonna lie that sounds complicated to my simple head. I wonder if I can find a wiring diagram to see the colours of wires I should be testing at?
I do know my good mate is very good with electrics and resistance checking etc so I can always rope him in.
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Post by Karl on Nov 10, 2023 20:02:10 GMT 1
I’ll get you the diagrams STu
If you post the reg no
Got any pids to read the resistances
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Post by studabear on Nov 10, 2023 20:13:41 GMT 1
PN55KLK is the reg.
Gonna sound really daft now, what's pids?
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Post by Karl on Nov 10, 2023 22:08:50 GMT 1
Sorry bud I mean any live data parameters
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Post by Karl on Nov 10, 2023 22:11:13 GMT 1
Something like that I’d go straight to the RCM
Air bag module
For corrosion bad pin grip
But like said anywhere on that circuit up to and including the clock spring/spiral cable/squib 🙃
What ever you reference it by
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Post by OldGit on Nov 10, 2023 22:27:03 GMT 1
Connector corrosion & pin grip issues tend to cause high resistance, the DTC is specifically for low resistance which is an odd one - a mutual short in the clock spring or elsewhere - even damaged insulation with water ingress providing a resistive path to ground could cause it. As Karl says, live data would be the easiest way of monitoring for resistance changes due to movement. - How long has this been happening for?
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Post by studabear on Nov 10, 2023 23:46:54 GMT 1
A good while 😄🙄
I can have a look for live data on Forscan or the KTS at work
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Post by chippie on Nov 11, 2023 11:36:17 GMT 1
PN55KLK is the reg. Gonna sound really daft now, what's pids? What a shit job working on these types of faults…I sooner replace brake pads…  Parameter identifier(s)….diag codes, can also be used as a trigger function on scan tools for capturing live data.. We can’t know everything, every day a skool day…Happy hunting Stu..  |
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Post by studabear on Nov 12, 2023 17:24:47 GMT 1
Done the brake pipes today, not a minute too soon.
Axle bushes next on the list.
Seen my mate who can help me Airbag investigations once we have diagrams and he said no trouble.
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Post by Dragon on Nov 12, 2023 21:22:46 GMT 1
PN55KLK is the reg. Gonna sound really daft now, what's pids? What a shit job working on these types of faults…I sooner replace brake pads… Parameter identifier(s)….diag codes, can also be used as a trigger function on scan tools for capturing live data.. We can’t know everything, every day a skool day…Happy hunting Stu.. Chinese proverbs say 'Be carefull of man who he say he does'  |
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Post by Karl on Nov 13, 2023 16:25:27 GMT 1
Here you go Sorry for the poor image Old diagrams are terrible   |
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Post by studabear on Nov 13, 2023 22:22:07 GMT 1
Thanksfor that,we shallhave to see how we get on. Still need to have a look at Live data available when i get a chance.
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Post by studabear on Feb 18, 2024 21:55:03 GMT 1
Just stripped this down today. Ordered a squib just incase (tested used) only £20
Karl, don't suppsoe you could tell me torque setting for sterring wheel?
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