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Airbag light, hazards, horn honking, no power and 911 call

Woods247

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#1
I ran my first day on RT660s today and somehow managed to cause the car to think it crashed. They have incredible grip. I’ve run hundreds of laps at this track and never had any issue other than fuel starvation on its long left hand carousel. At the end of the same carousel it panicked, killed all power, started flashing and honking then called 911. After pulling off track, it would eventually restart and drive normally back to pit, but the airbag light remained lit. I reset the ECU with my AP and the same thing happened during my next hot lap. There were no codes.. Just the airbag light.

I pulled the airbag fuse for the remainder of the day and didn’t have further issues but I’m wondering if anyone else has experienced this.. Is the only solution pulling that fuse? My only concern with fuse out is the wrench, abs and airbag lights are all lit up. It killed everything, which was fine but I’m not used to having my dash lit up like that. I replaced the fuse to drive home and all was fine.
 


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#3
Huh. Never heard of that before. What's the exit of your carousel like? Are we talking, like, a banked section and rough transitions like the infamous Nürburgring one or just a really long turn that's flat?

Also, have any of the rallycross drivers heard of this in our cars?

I know some people have had unexpected airbag deployments before in tracked ZL1s, but not in a Ford.

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M-Sport fan

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#5
What is strange is that the airbags did not actually deploy if the sensor detected enough force to 'think' that the car had crashed, and informed the BCM of such, and set off the dash light.

One of the reasons that even in the old, SCCA road racing Showroom Stock classes of yore (which were actually VERY factory stock cars with full safety equipment, and 50 tread wear DOT slicks) they REQUIRED the disabling (and even FULL removal??) of ALL airbags in competition cars. [wink]
 


M-Sport fan

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#7
Sensor system may not be as simplistic as
power + "open circuit" = "airbag deployment"
View: https://www.youtube.com/watch?v=mWSlwhYyOhI

Apparently they designed it to be analytical, presumably with the idea of preventing unintentional detonations... excuse me I mean, "deployments".

.
Or let's call it what it really is, an EXPLOSION. [wink] LOL
 


OP
Woods247

Woods247

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Thread Starter #8
Correct. No deployment. @TyphoonFiST I have the DHM crashbar. My crash sensors are attached to the DHM IC.

In regards to the carousel, it’s flat until the end (still accelerating around 100mph but not WOT). The end his a slight incline with a bump before a smooth WOT right handed onto a straight. At that transition from left to right is where it freaked out. I intentionally stayed off the curbs the second time and it still did it. The bump in the transition is noticeable but no worse than anything on the street. Perhaps it’s speed vs quick change in turn vs bump that caused a trifecta.
 


OP
Woods247

Woods247

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Thread Starter #9
I gotta think rally X guys must have experienced this. If not, there’s simply something wrong with my car. Perhaps it’s a sensor or the vibration on the intercooler like @TyphoonFiST could be thinking.
 


TyphoonFiST

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#10
Check the sensors for corrosion/ water intrusion and fraying of wires. Food for thought....Crapsler...er I mean Chrysler had sensors in the minivans a while back that were super sensitive to moisture and vibration. If the airbag light came on the sensors would be replaced and connector replaced if corroded or if you felt it would or could become an issue down the road for the owner*

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Woods247

Woods247

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Thread Starter #11
Check the sensors for corrosion/ water intrusion and fraying of wires. Food for thought....Crapsler...er I mean Chrysler had sensors in the minivans a while back that were super sensitive to moisture and vibration. If the airbag light came on the sensors would be replaced and connector replaced if corroded or if you felt it would or could become an issue down the road for the owner*

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That’s a very good possibility. They’re exposed behind my grill and the last weekend was wet. I’ll pull the cover off tomorrow and check and maybe apply a little dab of dielectric grease.
 


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#12
It very unlikely it's the connections. The srs system connectors are gold plated as a safety requirement against corrosion.

That’s a very good possibility. They’re exposed behind my grill and the last weekend was wet. I’ll pull the cover off tomorrow and check and maybe apply a little dab of dielectric grease.
 


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#13
Your inertia sensors got enough force to close the circuit causing the car to shut off its fuel system. It's probably due to where you currently have it mounted and not using the stock crash bar mounting locations. That's why I don't have a dhm crash bar.
 


M-Sport fan

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#14
I now wonder just how many g's of deceleration it takes to set the airbag light off, and then what level to actually set off the airbag itself??

Also, one would think that it might only be longitudinal deceleration that is sensed/detected by the sensor, but given the (at least front seat) side airbags now common in all cars, it must also sense lateral decelerative forces as well, no??

Could Woods 247 be getting enough lateral grip g's from those RT660s through that particular section of track, that it could be what's setting off the dash light?
 


Intuit

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#15
Take it to a dealer and they can pull the data; which presumably will allow one to determine exactly what set it off.

What I don't know is, how long this data is saved; whether it survives an ignition cycle.

1603510408347.png

EDIT: Next page...
1603510602656.png
 


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#16
The airbag light being on now means there's a fault in the system. It usually takes 2 impact sensors sending a signal to the srs unit to set off an airbag. OP should check his seatbelts as those have a firing mechanism that locks the seat belt in place. They need to be replaced as they're one time use. Also SRS system has to be reset by dealer. I'm not sure if forscan can do it. The SRS module may need to be replaced as well, depending on manufacturer as some of those are 1 time use too; others can be reused a few times. The SRS module could cost around 500 usd. This could end up being quite a costly repair for op.
 


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Woods247

Woods247

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Thread Starter #17
Your inertia sensors got enough force to close the circuit causing the car to shut off its fuel system. It's probably due to where you currently have it mounted and not using the stock crash bar mounting locations. That's why I don't have a dhm crash bar.
They’re not on the crashbar
 


OP
Woods247

Woods247

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Thread Starter #18
The airbag light being on now means there's a fault in the system. It usually takes 2 impact sensors sending a signal to the srs unit to set off an airbag. OP should check his seatbelts as those have a firing mechanism that locks the seat belt in place. They need to be replaced as they're one time use. Also SRS system has to be reset by dealer. I'm not sure if forscan can do it. The SRS module may need to be replaced as well, depending on manufacturer as some of those are 1 time use too; others can be reused a few times. The SRS module could cost around 500 usd. This could end up being quite a costly repair for op.
The airbag light is no longer on after resetting the ECU.
 


OP
Woods247

Woods247

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Thread Starter #19
The airbag light being on now means there's a fault in the system. It usually takes 2 impact sensors sending a signal to the srs unit to set off an airbag. OP should check his seatbelts as those have a firing mechanism that locks the seat belt in place. They need to be replaced as they're one time use. Also SRS system has to be reset by dealer. I'm not sure if forscan can do it. The SRS module may need to be replaced as well, depending on manufacturer as some of those are 1 time use too; others can be reused a few times. The SRS module could cost around 500 usd. This could end up being quite a costly repair for op.
Read post 1
 


OP
Woods247

Woods247

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Thread Starter #20
I now wonder just how many g's of deceleration it takes to set the airbag light off, and then what level to actually set off the airbag itself??

Also, one would think that it might only be longitudinal deceleration that is sensed/detected by the sensor, but given the (at least front seat) side airbags now common in all cars, it must also sense lateral decelerative forces as well, no??

Could Woods 247 be getting enough lateral grip g's from those RT660s through that particular section of track, that it could be what's setting off the dash light?
I think it’s the combination of high G left to extremely quick high G right that’s causing the sensor to freak. The RT660 has far more grip than any other tire I’ve run. Imagine going left at 115mph for 5 seconds then very quickly turning right (over a bump) while proceeding to WOT. Ford thinks that’s dangerous.

I didn’t need to pay a Ford dealer to reset my ECU lol. The AP can reset it. The warning lights are off and the system is active without problems. I doubt it has anything to do with the location of my front sensors but for shits and giggles I’m going to compare the location with a stock Fiesta ST.

I’m guessing others just pull the 10AMP #20 airbag fuse and hammer down. That’s going to be my solution for that track unless someone has a better idea. I need to find a RallyX guy. Their cars make far more abrupt changes in direction than mine does.
 




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