SERVICE AIRBAG SYSTEM LIGHT?

Tiny
DONSS396
  • MEMBER
  • 2007 CHEVROLET TAHOE
  • 80,000 MILES
I have a "SERVICE AIRBAG SYSTEM" LIGHT ON and acode Code# u0073. Any idea?
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Sunday, February 17th, 2013 AT 7:52 PM

29 Replies

Tiny
ASEMASTER6371
  • EXPERT
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.
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Sunday, February 17th, 2013 AT 7:59 PM
Tiny
DONSS396
  • MEMBER
Could it be a clock spring in the steering column?
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Sunday, February 17th, 2013 AT 8:02 PM
Tiny
DONSS396
  • MEMBER
I don't mean to be rude, but that is your expert opinion? Take it to a shop? Lol
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Sunday, February 17th, 2013 AT 8:18 PM
Tiny
JOSIERT
  • MEMBER
  • 2005 CHEVROLET TAHOE
  • V8
  • 2WD
  • AUTOMATIC
  • 43,000 MILES
My service air bag light came on yesterday morning, can it be something that I can change myself. Thinking it may be a sensor?
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Monday, July 13th, 2020 AT 6:11 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
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.
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Monday, July 13th, 2020 AT 6:11 PM (Merged)
Tiny
HLACEFIELD
  • MEMBER
Thanks for this post I had this problem and had to replace the clock spring cost me $143.00 FYI hope this helps.
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Monday, July 13th, 2020 AT 6:11 PM (Merged)
Tiny
JOHNFISHJR@GMAIL.COM
  • MEMBER
  • 2003 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 168,000 MILES
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.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
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
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
JOHNFISHJR@GMAIL.COM
  • MEMBER
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?
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
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
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
JOHNFISHJR@GMAIL.COM
  • MEMBER
I will have to test for power at pin 16, are you talking GM Tech II tool to monitor the BCM?
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Yes, that will work as well as a Snap On scan tool as well.

Roy
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
CROACHZ28
  • MEMBER
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.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
You are more than welcomed to start a new question with your concern and we would help you as well.

Roy
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
CROACHZ28
  • MEMBER
Thank you.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

We are always glad to help.

Roy
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
GREG_OJEDA1121
  • MEMBER
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.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
We just had another question on a similar car it was the BCM here are the replacement instructions in the diagrams below.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
CODY1111
  • MEMBER
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.
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Monday, July 13th, 2020 AT 6:12 PM (Merged)
Tiny
CHEVYFAN1988
  • MEMBER
I'm having same problem CODY1111. Have you figured it out?
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Monday, July 13th, 2020 AT 6:12 PM (Merged)

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