How to pull airbag light codes?

[CrustyJunker]

Looks much better than mine did! I ended up changing mine Willy-nilly since the damage was more obvious. -You're on the right track by properly troubleshooting. On mine, the rubber potting was all cracked, as well as the outer shell basically crumbled in my hand... Probably didn't even have to take the bolts off it was so bad. Ended up changing at least 3 of those in my truck's lifetime (that I can remember). Only other thing you can check (without your scanner here yet) is the wires leading to the cab. It would be rare and far-fetched to just come unplugged or pinched all of the sudden, but I guess couldn't hurt...Should be bright yellow connector with an orange locking tab. There's one near each sensor and I think one on the driver-side frame rail next to the engine. I apologize if that isn't accurate, it's been a long time since I've looked! There should also be a fuse for the system, too.

 

[Blue Turd]

Looks much better than mine did! I ended up changing mine Willy-nilly since the damage was more obvious. -You're on the right track by properly troubleshooting. On mine, the rubber potting was all cracked, as well as the outer shell basically crumbled in my hand... Probably didn't even have to take the bolts off it was so bad. Ended up changing at least 3 of those in my truck's lifetime (that I can remember). Only other thing you can check (without your scanner here yet) is the wires leading to the cab. It would be rare and far-fetched to just come unplugged or pinched all of the sudden, but I guess couldn't hurt...Should be bright yellow connector with an orange locking tab. There's one near each sensor and I think one on the driver-side frame rail next to the engine. I apologize if that isn't accurate, it's been a long time since I've looked! There should also be a fuse for the system, too.

All yellow connectors under hood are in fact plugged in and look to be in good shape. It is most likely the sensors, which unfortunately are no longer available from GM, so I need to find a decent pair from a junkyard or from another member on here. What's weird is nothing different happened to the truck before throwing the airbag light. Wasn't taken on a bumpy road or even rained on. It did radomly get warmer though, so it might have expanded ever so slightly for its last time and broken something internal in the sensors.

 

[jw_96]

So I did some more searching. I still do not believe that there is a way to jump some magic diagnosis pins (like you can on these trucks for CEL and ABS lights) to read the codes. Even if you do guess right and replace the part throwing the light, I believe you still need a scan tool to clear the light (supposedly removing power does not do it). So far I am looking for a ~300 scan tool that can pull the air bag codes on these trucks. Using this sort of an excuse to buy new tools lol, as I have been getting by with a bluetooth phone OBD2 scanner and jumping pins on stuff. A "real" OBD1/OBD2 scanner will be a good tool to have. Currently have a few in mind that I am looking at that supposedly pull these OBD1 GM airbag codes. If anybody has suggestions on a scanner that is known to work for this let me know!

If I find one that does work I will update this thread.

What do you jump to read CEL and Abs lights?

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[Blue Turd]

What do you jump to read CEL and Abs lights?

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https://www.obd-codes.com/faq/read-gm-2-digit-obd-codes-free.php

Pretty much you jump some pins on the diagnosis port under the steering wheel with a paper clip or small wire, then turn the ignition on and count the flashes. The number you get from the flash corresponds to the problem throwing the light.

ABS codes are done the same way but I believe you jump pins A and H in the diagram posted in the above link.

This is only for 95 model year and older vehicles. The pins are different on a 96 and newer obd2 vehicle so I would just use a cheap scanner or bum on from autozone or whatever for that.

 

[CrustyJunker]

All yellow connectors under hood are in fact plugged in and look to be in good shape. It is most likely the sensors, which unfortunately are no longer available from GM, so I need to find a decent pair from a junkyard or from another member on here. What's weird is nothing different happened to the truck before throwing the airbag light. Wasn't taken on a bumpy road or even rained on. It did radomly get warmer though, so it might have expanded ever so slightly for its last time and broken something internal in the sensors.

Mine would do the same. The not-so-obvious junk ones were intermittent. Light would stay on after start-up...Maybe 1 day a week? Then eventually on all the time. At least it's showing a fault. The one that made me nervous rusted off, swung by the cord, and gently tapped on the frame over bumps and corners... Nothing ever happened, but thinking to myself "how long has that been going on?" It probably takes a good smash to set one off... However, the picture of getting punched in the face at highway speed for no reason. -Yeah, I'll pass.

I've always been curious as to what's inside one of those sensors. I ohmed mine out and never had one read open, but I don't know if that's a good test or not. I ended up tossing all of the old ones a couple years ago and didn't take the time to dissect one. I should be due for one to rot off any time here. Maybe it's science time!

 

[Blue Turd]

I'll totally disect one for gmt400 science if they turn out to be bad. I believe on the inside it's sort of like the mechanism used inside a clicker style torque wrench. If there is enough energy to unseat the sprung sensor from its standard position and the computer sees the car is going over a certain speed, it will go off.

 

[Blue Turd]

Got my scanner in the mail today. Unfortunately it was not able to pull the airbag codes on my truck. Still a total keeper because it was able to otherwise pull CEL codes (I do not have any) and every bit of sensor information from the truck. I could see coolant temp, A/C activation, 02 sensor values, fuel ratios, the whole deal. On my <1996 cars that are officially OBD2, the scanner easily accessed airbag, abs, and engine information. These newer vehicles have even more data sensors to read and graph.

As for my airbag light, I talked the the only shop around here that I trust to touch my vehicles. They said that they would plug in their fancy Snap-on scanner free of charge and let me know what is up. The diagnosis tech was not there today, so they said to bring the truck back tomorrow.

I was also able to track down a couple different sources from local junkyards, they claim "grade A" and cost about 15-30 dollars a piece. Not bad price at all, so I will probably replace both, but keep any working ones as spares.

 

[Blue Turd]

The tech who is real good with pre obd 2 diagnosis is out of town so I have not gotten my codes pulled. Fortunately I think I found my issue to the problem. I was doing some more general air bag research and I totally forgot about the clock spring! Usually you know it's out when your horn or steering wheel controls don't work. My truck doesn't have that fancy stuff on the wheel (and horn is separate circuit so works fine) so I decided to investigate.

After safety removing the airbag and isolating the clock spring I went to test the continuity with my multimeter. First I was disappointed that both wires checked out and seemed to work. Only out of curiosity did I try one wire to the other wire and bam there was continuity. That means there is a short somewhere in the clock spring which is most likely the culprit for setting off the airbag light.

This is enough information for me to pull the clock spring out and verify it had in fact shorted out. If that is the case, I will be ordering a new one and updating this thread with the results.

 

[CrustyJunker]

Hope you find it. Are those clock springs readily available? I'm not having any problems with my system yet, but every day my truck gets a little bit older!

 

[Blue Turd]

Hope you find it. Are those clock springs readily available? I'm not having any problems with my system yet, but every day my truck gets a little bit older!

Yes the clock spring is readily available online for around 100 bucks. It must be a much more common issue than the sensors, considering the clock spring is available still and the sensors are not. I do have to rent a steering wheel puller from my local auto parts store to get to it, but thats not a big deal. It is a fairly easy job and there are many videos of the procedure posted online.