Stupid question? Airbag sensors location?

Hi Guys,
If you've seen my other posts (or my profile pic), you know that I'm repairing a wrecked 2013 SR5. (I'll include some before after pics here too for reference) I'm making some significant progress, but had a thought as I was going to replace my driver seat belt (due to pretensioner be triggered in accident) as well as the steering wheel bag deployment and my subsequent replacement of that and the knee bag (which I've already done).
So....where are the sensors that trigger the bags to deploy? (duh).....the bumper wasn't hit directly (a high hit)....but I haven't run across any 'visible' sensors.
Is it all controlled from some inertia system? or are there sensors that need to be replaced or reset???
I don't want to install the steering airbag and it deploy because the sensor is damaged. I know this sounds stupid....so, maybe I just am!!!!
Thanks for any 'positive/supportive' help in advance
before:

After:

 

Maybe #8 here? It’s not in the bumper. It has to be an inertia type system.

https://www.sparksparts.com/v-2013-...d--5-7l-v8-gas/electrical--air-bag-components

 

Ok...I lied after looking at this diagram...Thanks timsp8! There is a #9 on each side of the truck in the location indicated. Now I guess I just need to determine if they 'reset' or will require replacement. Maybe someone on here knows how that works??

 

As the diagram shows it has two front impact sensors and two side impact sensors. The ACM (airbag control module) is the brain of the system. It’s on the transmission tunnel under the console and has accelerometers in it to help detect an impact. (This is generally how rear end impacts are detected by the truck as there are no rear impact sensors)

The impact sensors send a signal to the ACM to tell it to deploy the airbags in a collision. As long as the sensors and wiring are not damaged you should be good to go.

Any impact felt by those sensors will cause them to send another signal to the ACM to deploy the airbag again. If a bag is already deployed the ACM knows due to resistance on wiring to the bag and will have a trouble code until the bag is replaced with a good one and codes cleared. Airbag troubles codes are some of the more difficult ones to clear. They are generally stored in non violate memory and require a scan tool to do it. Unhooking the battery is not enough to make it forget the code.

Side note, anytime the airbags are deployed by the ACM is also triggers the data recorder in the ACM. It logs things like speed, brake pedal application, engine rpm ect and can be downloaded to see the severity of the collision. This means your ACM has a record in it for the crash the truck was involved in. You need special software and cables (Google Bosch CDR) to get the data out and read a report. Some police departments have it and some engineering firms have it. I do it all the time as an engineer in automotive accident reconstruction

 

I would recommend sourcing a copy of Toyotas Techstream online. “Secondary” versions can be had if you look hard enough. You will need to get a proper cable to let the laptop communicate with the truck through the OBD2 port.

Techstream is the best tool for seeing inside the ACM, reading and clear trouble codes specific to the airbags. It really gives you the ability to see inside and understand what’s going on with almost every ECU of the truck.

 

Wow...a BIG thank you Jeff_5_7!! the sensors themselves seem fine, no direct impact and was able to plug back in. I will search to see if I can source the cables and Techstream to clear the codes. So it sounds like I am OK to go ahead and install the new Steering wheel airbag and seatbelt (as mentioned already did the kneebag), but I will still have the dash warning until I can get it cleared.
Thanks so much for the help!!! Much appreciated......
George

 

The fact the knee airbag didn’t blow out as soon as you installed tells you that you are good to go.

Some shops with higher end scan tools can clear airbag codes.

Slight chance when you get all the airbags in and the system is happy, the light goes out it’s self

 

That would be AWESOME...I really need some luck. I'm upside down in this restoration due to some 'unexpected things' thanks to a thief!!!!

 

@geoyodas8 Did you end up resetting your airbag controller and everything works now? How did your experience with techstream go?

 

Hey....Great questions! So, after I installed the steering wheel (with good bag), replacement knee bag and the driver seatbelt (pretensioner blew). I crossed my fingers, and to my surprise, the airbag light went off...BUT! it came back on(not sure when). After researching some more, it seems that collision data is stored in the SRS Airbag control module and it needs to be wiped from the controller or the controller replaced with a new one. There are a BUNCH of companies out there that will take your used controller and wipe the collision data. But, I've recently called several of them and NONE of them guarantee that the light will go out and of course have a LOT of disclaimers. So, I'm still thinking about all my options. (probably going to send off my controller to be 'cleaned') - but its going to be some work, because it looks like the module is located under the console (below the radio, climate controls basically on the floor on the tranny tunnel)
Techstream is another story......So, I got the 'free version' after buying the cable online. I've tried several versions of the software and not having a whole lot of luck. I was able to delete the codes for the O2 sensors that I replaced after fixing the exhaust system. (so far check engine is still off).....but most of the other controllers aren't responding. I don't know if it is my truck (because of the accident) or the software being "bootleg".....I have 4 Toyota's, so I did connect to my Camry and it was 'better', but still some systems unavailable which leads me to believe it is the software version that I have.
I really wish there was a Techstream guru that could help me out.......I was hoping to use it for things like programming keys and key fobs....but not able to do that with what I have apparently.
Thanks for your interest!

 

Have you tried talking to a local body shop that you trust about it? They might be able to give you pointers on how to get the airbag systems working properly. Hell, you could try reaching out to Toyota themselves. Never hurts to ask.

 

Might give it a shot, but everybody is 'non-committal' on airbags....I guess no one wants to be liable if the go off when they shouldn't or vica versa! I just wish I could get FULL functionality with the Techstream and do it myself!

 

Great info Jeff! What other info can you get from the log? Can you tell if the truck got airborne? Or any way to tell a person was mashing through 3 foot whoops when the bags blew? How long before and after does it record data?

 

Asking for a friend, I assume?

 

I'm not sure that you need techstream to reset. Just need a code reader that scans airbag codes. Unless your issue is specifically because of the control unit having stored accident data you may just have a code stored that needs to be reset.

 

I would be very surprised if having data stored in the ACM is the problem but it could be. Most newer ACMs can store multiple generally 3 events. Deployment events when the bags go off are frozen in the ACM, when all 3 slots are full it has no room to write new deployment data so this could be the problem.

For reference, my 2007 has 2 events saved in it. I downloaded it when I bought the truck. Both of mine are non deployment events however so they are not frozen in memory and can be overwritten by a deployment. I have been driving my truck for 2 years with this data in the ACM with no airbag light on. I have read hundred of download reports with older stored data in them. Long story short “clearing the crash data” might only fix yours if it’s full (3 events)

The ACM is on the center tunnel under the console. They try to locate it as close to the center of gravity of the vehicle as possible. This helps the internal accelerometers record accurate data.

If you really want to, remove the ACM and mail it to me. I can take a look and see what data is stored in it. I don’t think I have the ability to clear the crash data as you need an ACM with no accident data in it to copy of memory from into yours.

I would focus on getting Techstream up and running to see what trouble codes are in the airbag control module. Is the communication network with all the ECUs working? No wiring issues with the CAN bus?

 

Generally they do not record data in the Z plane up and down. However some of the newer ones 2018+ from manufacturers are recording ALOT more data. I read a report out of a 2022 GMC and it has Lat and Long location data for where the accident occurred for example.

Almost every vehicle 2010 and newer has a recorder in it. A lot of vehicles 2000-2005 started recoding data. Toyota, Ford, GM, Chrysler/Dodge we’re all major brands that started earlier than others.

Most record 5 seconds of data prior to the airbag deployment. So deployment is time zero and you get data at 0.5 or 1.0 second intervals for 5 seconds back from time of deployment. Milliseconds after the airbag goes off the data is already saved in the ACM. It keeps a running buffer of data and when airbags deploy it saves the last 5 seconds of data in the buffer to ACM non violate memory. Unhooking the battery or removing power to the ACM will not cause it to forget the data.

Any deployment record is hard locked or frozen into the ACM and can not be overwritten. That means your airbag could have gone off years ago and the data is still in the ACM. Generally they can store 3 of these events before memory is full and ACM needs replacement.

Non deployment events, times when the truck ACM wakes up and is saying “do I need to deploy the airbags”, “are we getting into a wreck?” are stored also but they are not frozen or locked. So they can be over written by newer events. Generally you need an instantaneous drop in speed of 5Mph to get a non deployment event stored. Say you are going 70Mph and hit a big pot hole that slows you down to 65Mph almost instantly it would probably record this. I see a lot of fender benders, rear end bumps ect recorded as a non deployment. You hit something with the vehicle but not hard enough to where it decided it needed to deploy the airbags.

Almost all of them record acceleration forward (longitudinal) and side to side (lateral). Most also have Yaw rate data, ie is the truck trying to spin out or fish tail in one direction. You can use this data to get a general idea of vehicle movement direction.

Speed, Throttle Input, Brake Input, RPM, are almost always recoded. Steering wheel angle can be at times depending on manufacturer.

If you are clever you can determine if the vehicle was airborne. I had a 2017 Raptor that was jumped and then in a bad rollover. Throttle input and Speed were high but at some recordings of speed you saw big spikes or increases. This is because the wheels were in the air. The speed signal is derived from the wheel speed sensors. Unload the truck in the air and the wheels will spin faster. This made for rapid increase in Speed on the recorder. Even in a Raptor at 100% throttle these speed increases where unrealistic so you knew the wheels were in the air. No vehicle can accelerate from say 70Mph to 85Mph in 0.5 Seconds.

More importantly physical damage to the vehicle would tell you about if it was airborne or not. Seeing the damage to the truck in person would tell alot about what happened. Tie that in with the recorded data in the ACM and it’s not hard to figure out the full story.

I have probably read over 500 download reports from all kinds of cars and trucks. Done hundreds of them myself. If you guys really wanted a could share a sample of some data from a report.

 

I'm working on a similar project but side impact. https://www.tundras.com/threads/jus...a-how-about-some-advice-0.96367/#post-2444664

After sending my airbag controller in for reset I still have a code, so I'm troubleshooting whether it's a second unseen sensor or if the controller reset didn't clear this problem.

I have my interior apart, the center console isn't nearly as complicated as it seems, get a good interior trim removal kit, and you just need screwdrivers and a small socket set, and maybe some wrenches to get at the bolts holding the controller in because it's a tight area.

I'm also working on getting techstream up and running. I found a source but it's paid, not sure how much yet, I'm waiting to hear back.

 

Wow. Thank you. That was very informative! Do you work for an insurance company? So who gets access to this data? And yes, we’d like to see some sample data… preferably in the offroad crash variety.

 

Just out of curiosity - what is the memory size on an ACM? Could one be designed that stored the last few seconds of video footage in non volatile memory?

Seems like that would be a really helpful feature given how many vehicles have full 360 cameras these days.

 

I work at an engineering firm that provides consulting/expert witness services for automotive accidents. Most of the clients who hire us are insurance companies or large companies involved in litigation for personal injury claims. The lawyers for these companies are the ones that actually hire us but a lot of them represent insurance companies. Generally we only get involved in higher value cases when settlement demands are $100,000 up to millions if not hundreds of millions of dollars. We do some small fender benders on occasion but generally people don’t want to spend a lot of money in services/billing on these smaller cases.

Unfortunately a large majority of accidents we are involved in have at least one fatality or major life changing injuries.


Due to confidentiality agreements I can not share anything work related. We see photos and videos but they are strictly
monitored. For example a big national trucking company doesn’t want dash cam video from their 18 wheeler showing bad accidents just free floating around the internet.

As far as download data it’s technically the property of the owner of the vehicle. Before we ever do any downloads we get authorization to obtain the data.

Police or law enforcement will take it on the spot sometimes with a warrant if the owners are trying to hide something. I’m other instances the insurance company ends up buying the wrecked vehicle. As the owner they then easily authorize a download.

NHTSA has a database of public crash information. I can look through there and share things as it’s not involved with my work and is a public database run at a federal level.

 

It’s small and text only for now. It’s actually regulated by federal motor vehicle law on what data is to be reported. Manufacturers have to meet these requirements to sell in the USA. Some manufacturers go above and beyond others do the bare minimum to be legal.

I don’t know that we will ever see photos/video stored in ACMs but it’s not really that big of a deal. Almost every Toyota 2018+ takes pictures with the forward facing camera when the radar senses a possible threat. You can actually get this data with Techstream and some tricks.

The manufacturers are starting to record photos at least for now but every system is specific to manufacturer and requires different tools/software to get it out of the ECUs. They are storing this stuff in memory of of ECUs that are not the ACM.


It’s kind of controversial in a way. A lot of people don’t know it exist. Some people think it’s pretty cool, others get mad and think it’s an invasion of privacy.

 

Can the front sensors be accessed with the bumper on or does it have to go?

 

On mine, you can access the SRS sensors with the bumper on...they are located above the bumper on the radiator support (going from memory, might have a photo or can take one if it helps)

 

Did you need to remove anything to get to them?

Thanks!

Edit, I just found both of them. The passenger side is semi-accessible, driver has a slew of add on harnesses I installed in the way (SC intercooler pump, 2018+ headlight and the battery)

Hopefully, my error is gone & I don't have to deal with them.


Thanks!

 

Good luck....glad I read the whole post as I was walking out to take a picture for you. Hope all goes well!!

 

Thanks, I appreciate the help.

 

I was able to get both out & cleaned their contacts, hopefully, my issues are done.

Thank you for the help!

 

When I said I got it out I meant the electrical connector, there was a 15% off sale so I ordered them and the error has come back a few times, it clears but comes back. What fastener is attaching it? I Can't see & have tried everything that fits into the opening & nothing grabs, it seems to be a hex & I have tried several.