SERVICE AIRBAG SYSTEM LIGHT?

This sounds like the airbag module has gone bad these videos will help us fix it.

https://youtu.be/rTtAnsOlZU4

Please run down this guide and report back.

DTC U0073 72
Control Module Communication Bus Off Alive Counter Incorrect

CIRCUIT/SYSTEM DESCRIPTION
The high speed GMLAN serial data circuits are high speed serial data buses used to communicate information between the control modules. Typical data transmission speeds must be high enough to ensure that a required real-time response is maintained. The high speed GMLAN serial data circuits also connect directly to the data link connector (DLC).

CONDITIONS FOR RUNNING THE DTC

•Supply voltage to the modules are in the normal operating range.
•The vehicle power mode requires serial data communications.
CONDITIONS FOR SETTING THE DTC
The module setting the DTC has attempted to establish communications on the GMLAN circuits more than 3 times.

ACTION TAKEN WHEN THE DTCS SETS

•The module suspends all message transmission.
•The module uses default values for all parameters received on the serial data circuits.
•The module inhibits the setting of all other communication DTCs.
CONDITIONS FOR CLEARING THE DTC

•A current DTC clears when the malfunction is no longer present.
•A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
DIAGNOSTIC AIDS

•An intermittent condition is likely to be caused by a short on the high speed GMLAN serial data circuits.
•This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the symptom Scan Tool Does Not Communicate with High Speed GMLAN Device to.
•Refer to Data Link References for the specific modules using high speed GMLAN serial data. See: Powertrain ManagementComputers and Control SystemsInformation BusTesting and InspectionInitial Inspection and Diagnostic OverviewData Link References

Please let us know what you find.

Could it be a clock spring in the steering column??

I don't mean to be rude, but that is your expert opinion? Take it to a shop ? Lol

my service air bag light came on yesterday morning, can it be something that i can change myself. thinking it may be a sensor?

Need a scanner to find fault many possibilities which you can get from Amazon for about $30.00. Here is a video to help you see what to do to fix the problem.

https://youtu.be/gnSGfEqrf_w


Here is the scanner

https://www.amazon.com/gp/product/B007XE8C74/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=2carprcom-20&creative=9325&linkCode=as2&creativeASIN=B007XE8C74&linkId=2b1553d47faedf8e31ccd8a7833c6a58


Please run down this guide and report back.

Thanks for this post I had this problem and had to replace the clock spring cost me $143.00 FYI hope this helps.

July 4th went to a friends house and truck would not start. Unknown driver, locks do not work, remotes do not work, windows will not work. Cranks starts and shuts off. A battery disconnect brought everything back to life and off I went. As I was going down the rough driveway dash lights were on and off, the chime would activate ABS and brake light would come on and go off again. Finally all the gauges quit, locks and windows stopped working again, no dome lights, no 4x4 activator, no gear selector, no reverse lights. I do have speedometer, tachometer and the odometer works. I have the airbag, ABS, and battery light on in the dash but the alternator is charging fine. The rear HVAC is not working and the front works but will not kick in the A/C. Sunroof works. Of course I have no radio but I can operate the seats. The display on startup is unknown driver but it starts and drives fine. Auto headlamps turn signals and brake lights all operate.

A mechanic had me do some tests and said it sounds like the PCM fried. Freshly programmed PCM installed and all the same issues but will not run either. The pass-lock reset procedure could not be done because the lock symbol only stayed on for a couple seconds verses the ten minutes it is supposed to stay on. So, old PCM back in, it runs but no A/C with windows that will not work is not good.

With all the computers in the vehicle it acts like BCM is bad but with the no A/C or gauges that sounds like the PCM. So I am at a loss, this all seems to be due to an extremely rough driveway so could something have shaken loose verses a computer problem. Or did something short wiping out a few different computers/modules. All fuses test good. The week before I had suspension work done which required a lot of air hammering on the torsion rods, lots of vibrations.

Good morning.

Definitely not the PCM. All the controls you are having issues with are related to the BCM.

Check all the connections on the BCM and see if there are any loose, damaged or burned pins. If that is all okay, then you will need an advanced scan tool to access the BCM and see if there are any fault codes as well as monitoring live data.

It does sound like a failing BCM but need to be confirmed here is video that can show you how

but to be sure lets do a CAN scan which is the future of automotive repair you can get a CAN scanner from Amazon for about $50.00 here is a video to show you how.

https://youtu.be/InIlnsjOVFA



Roy

Thanks Roy, my gut was with BCM but I let an expert talk me into PCM.

My vehicle shows a short somewhere. You know the old trick, disconnect the negative terminal from the battery and put a test light in there. Could this be the problem? I have pulled every fuse looking for this short without any luck. I have been pulling connectors apart hoping to find something but so far no luck.

BCM connectors all look clean and shiny. Still had the short with all the connectors off the BCM.

I have a BlueDriver code reader but it will not connect with the car. Seems there is no engine running signal at the port. It connects fine with my 2003 Silverado. Can the BCM interrupt the engine running signal to the test port?

That test is for a drain, not a short. If you are looking for a drain you measure amp draw, not voltage.

Check you fuses. Pin 16 of the DLC is for power to the scan tool. That circuit is fd from a fuse for the auxiliary power outlets.

You need a real scan tool to monitor the BCM information.

Roy

I will have to test for power at pin 16, are you talking GM Tech II tool to monitor the BCM?

Yes, that will work as well as a Snap On scan tool as well.

Roy

John, I am having the same problem with my 2004 Tahoe. What did your problem turn out to be. Mine will start and shuts right back off. Security light is not on. I don't know what to do for both problems. Any help would be appreciated.

You are more than welcomed to start a new question with your concern and we would help you as well.

Roy

Thank you.

You are welcome.

We are always glad to help.

Roy

Were you able to find out the problem? I have the exact same problem on my 2004 Tahoe and I’ve tried everything and nothing seems to work,

We just had another question on a similar car it was the BCM here are the replacement instructions in the diagrams below.

I have a 2004 Tahoe. the gauges wont work, A/C wont work, windows and locks wont work. ABS light and airbag light is on and it wouldn't start. changed the BCM and it will run, but none of the other stuff will work.

I'm having same problem CODY1111. have you figured it out?

We give opinions on the issues and most of the time we never hear back from the customer. If it was not repaired, we will get responses for more help.

If you like, you can start a new question with your exact issue and we will be glad to help.

Roy

I have not figured it out I've checked a few ground wires but have failed.to fix it I haven't checked the ground that goes to the PCM my obd2 is has power but is not communicating so maybe the PCM is bad or the ground is bad if i.do figure out what the problem is I'll will post and let you know. if you figure out please let me know.

Please start a new question. then we can help you with the problem.

Here is the link: https://www.2carpros.com/questions/new

Roy

DTC B0100 - Front End Sensor Performance. I doubt the front end sensors are bad, because I think they are simple mechanical devices. But I can't find anything more on the subject. I can't even locate a replacement part. I have pulled the connectors and checked for damage or corrosion; they are clean. I am getting ready to pull the device and dismantle it. It could also be an open wire, but the vehicle is still young. Unable to clear the code. Any experience with this? Thanks.

Where were you guys? I guess this really is a do it yourself thing. Have an airbag problem? First get a scanner that reads airbag codes. Try Harrison R&D in Texas (obdscan.net). Read your DTC; mine was a B0100 left front impact sensor. Next get a manual; try Mitchell1 (online). Don't work on airbags with out a good manual. You have to disable the zones to prevent accidental deployment ($$$ and embarassment; think the mechanic would have a good laugh about that?). For me, the manual wanted to isolate the wiring to the sensor and check for shorts and opens. That was too much work; car is not that old. So, I disabled the front zone and switched sensors; the DTC code came back B0103 right front. That pretty much was enough to go buy a sensor ($75) from the dealer and kill the problem. I still think overall I spent way less, I'm tooled up for the next thing and I don't know about you, but I like fixing things.

Computer problem
2004 Chevy Tahoe V8 Four Wheel Drive Automatic 58673. miles
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My "check airbag" light came on, so I took it to the dealership and they ran a diagnostic on it. The mechanic told me that the two crash detector sensors located by the radiator were bad, one was corroded and the other had a short in it. 319.68 for parts...ugh. Then he said that he would call GM to see if they could help on these costs. Does that seem weird to anyone? Is there something they may not be telling me, or is there another to fix this sensors, can i do it myself (when i say myself i mean my husband). thanks for any info.

I am not sure about this area of the vehicle, although it does seem strange. I have never heard of an airbag sensor bieng bad much less two on a 2004. I would get a second opinion but this is not an issue I would attempt to address myself, like I said I dont know much about it but more importantly I know the consequences of a mistake in this area. All I can say is if you or your husband attempt to repair or modify your airbag sensors MAKE SURE THE BATTERY IS COMPLETELY DISCONNECTED!!! I know airbags are expensive and you never get that powdery crap all out ;)

i recently had the "service airbag" light come on. i was going to take the truck to a mechanic to get that fixed but when i was cleaning it out to do so i found a part that has the same symbol for the airbag and it looks like something electrical. i have a part number and i was wondering if i could just put it back on myself but i just cant find where it goes... the part number is 15188374.

I don't have a cross reference or interchange to GM parts, so check with GM parts dept.
If you can't find it repost and I will investigate further.
You can also call local parts stores and ask them to type the GM part number into their interchange software to get part ID.


You should first get the codes read from the diagnostic port, Air Bags set a "B" body code.

You always want a professional to work on an airbag system, accidental deployment can be very dangerous, as well as expensive.