Jason Novak

I was fixing my turn signal and when i was done the air bag light came on. After some searching, it sounded like this is normally caused by a mis-alligned and broken clock spring. I replaced it with a new one, same problem.

So I took it into the dealer, it had codes dtc b1024 and b1071, "driver deployment loop short to ground". The guy gave me a printout the diagnostics he was following from gm's site. He got to the point where he was testing DRIVER SENSELO, both bags showed like 4v, about the 3.3v minimum, so the end result is a new SDM ... a $320 part. Second opinions anyone? The only thing I think I could have shorted was the original clock spring, and in all my searches I've never seen anyone say it took out the SDM when the mis-aligned the clock spring.

01WS6/tamu

iTrader: (37)

Clock spring took a chit. replace it and go on about your business as normal.

Jason Novak

I replaced the original one I probably misaligned with a brand new one that I'm pretty sure I put in correctly this time and still had the air bag light ... would there have been a way for the service guy to tell the difference between the clock spring and a bad SDM ... are there different codes? I can put a meter on each end of the clock spring to make sure it's still alive?

2002_Z28_Six_Speed

iTrader: (19)

Nope. That would only be the case if the Driver's deployment loop was OPEN.

This is a SHORT.

Either the deployment loop is shorted to the body or the module needs to be replaced.

This sounds like he is going to have to pull the carpet and inspect the wiring. If he wants to buy a new module he would only have to pull the console and try to replace it.

He could always buy the module from the dealer and if it doesn't work try to return it and say you didn't use it.

He could pull the connectors from the CSW spring and the module and then run a cont check.

Glad you finally did get the codes, Jason, it makes this a ton easier!!

01WS6/tamu

iTrader: (37)

Sorry missed that little fact makes all the difference. Does your airbag have the plug that goes directly into a molded socket on the back of the airbag or does the airbag have an electrical pigtail that the clock spring plugs into. I have seen this pigtail get pinched a couple of times causing the driver deployment short to ground code. Thus setting the codes you are experiencing. You might pull the airbag out just to double check it. I was in the middle of working on a diagram for something else at the shop when I just glanced at your post.

Jason Novak

Thanks for all the help, 2002_Z28_Six_Speed

It seems that since I was only in the steering column that it wouldn't be short elsewhere ... unless the short fused some wiring together. I never did test that the new spring was good, I will test it. It sounds like there are some wires I can test at the SDM going to the clock spring for a short?

If it does come to replacing the module, do you have take it somewhere to sync up with the other computers? It looks like it would be easy to replace, I've seen it in the console before when I was doing other things. They quoted $180 in labor to replace it ... that seems a little high unless I'm missing something...

Finally, is it possible a mis-aligned clock spring could have caused all this? I'm not sure if I want to ever mess with the signals again if I don't know what the issue was

Jason Novak

01WS6 - I believe the airbag has a little wire, like 2-3 inches, and connector is attached to the back of the airbag. Do you mean to try it with the air bag not screwed into the wheel?

Jason Novak

Ok, I did some testing this morning and here's what I got.

Testing the clock spring, I realized the clock spring has to be connected into the car harness ... some kind of self-shorting connector? Once I did that, both ends of the clock spring showed connectivity, and only on their own wires, no short there.

I then unplugged the connector from the SDM and tested from that harness back to the connector that the clock spring goes into, pin 2-white and pin 3-green for driver side air bag at the SDM. They both showed connectivity, and no shorts.

I put the air bag loosely back on the wheel, not tightened down, and hooked everything back up ... still have a light. I noticed there was an indention in the little pigtail on the air bag.

So I'm thing maybe that had gotten crushed and the short is in the bag itself? I think I need some detailed help before I can test that myself, if it's even possible without special tools - I don't want to stick a meter across air bag wires and have it blow up.

If not that, it sounds like the SDM is dead? Pins 2 and 3 would be the only two wires shorting at the SDM to test?

ps ... now that I've seen my SDM module and have the part number, a search on eBay brought up one result...http://cgi.ebay.com/ebaymotors/_Car-...m330240509401& ... it's from a pontiac but it should work being the same part number? Just need to worry about coming from an uncrashed car and it will sync up?

2002_Z28_Six_Speed

iTrader: (19)

'

WOWWWWW That auction is a real deal if its legit and thats the real price.
I paid 125 dollars for a drivers airbag on ebay couple of years back

If the module has the same part numer it should work fine.

But yes you want one from an unwrecked car. Perferably in new condition

Jason Novak

I'm trying to see if he'll break up the set, otherwise I think I can get one in the for sale section.

Is there a way to test the air bag itself? Since I couldn't seem to find a short anywhere I tested in the driver side wires, I want to make sure the bag itself isn't bad - or that it will just blow the new computer.

Does the new module have to be synced up or the codes cleared by the dealer? Looking around some people seem to say it does, some it doesn't, possibly a 99+ only issue?

2002_Z28_Six_Speed

iTrader: (19)

There is NO WAY to test the air bag and I wouldn't even put the slightest current or voltage to it. It is possible for the airbag to fail but they have super high quality control. Unlikey but possible.

It is true that the airbag module sends a small current down the deployment loops on startup to verify that the system is working correctly. I wouldn't try to duplicate this. Injury could result.


As for having the module synced I didn't have to do that. The codes just eventually went away.

Jason Novak

I was just wondering if I may have shorted the bag out with all my messing around, and perhaps it could be tested for conductivity. I couldn't find a short anywhere in the passenger side wiring as the code would indicate, so I'm not sure where that came from - it would be nice to know just for peace of mind in case I ever need to mess around with the signal again now that I better know what I'm doing and worry about the module dying

Jason Novak

Here's an update on how it came out ... the auction didn't have any bidders, but the guy didn't want to sell just the module. Luckily I found a module in the for sale section for $20. Just got it today, put it in ... air bag light is gone Thanks for all the help.

2002_Z28_Six_Speed

iTrader: (19)

So, I figured. Congrats on the cheap fix.

That auction was a good deal either way. The driver's airbag had to be worth at bare min 100 dollars.

Oh well. Sounds like you have most of your problems wrapped up for awhile.

erkan7g

Hi Jason

I read all the conversation .you replace SDM on the end. I guess SDM module is airbag control unit right? if so did you need to program it after replace? also can I ask what is your car model ?

I have pretty similar story, I fixed my turn signal and my srs light came on. very annoying issue. I tried many things as you did but seems like I also have faulty SDM or control unit.

Jason Novak

I replaced it in my 98 Z28. The module is under the center console storage if I recall. I just got the part number off it, same part as a firebird, and bought a used one off eBay > no programming needed. Still have the old pic
http://www.merlinsoftware.com/filestore/DSCF0845.JPG

bill122b

backprobed yellow airbag connector to GROUND [the car body] is 2100 ohms not exactly a short, unplugged the srs module under the center console just behind the gearshift now over 4 megohms on the green wire to pin3 replaced the srs module with a $30 ebay used one back to 2100 ohms with the replacement srs, measured pin 3 to the srs case 2100 ohms again. Bad srs, maybe, if someone has a good srs would measure pin 3 3rd pin from the left to the case with a dvm I would be in their debt. Thanks, Bill in Torrance.

bill122b

you can safely measure the clockspring and airbag with a digital voltmeter it should be 3 ohms or less its the yellow plug underdash hide under the dash if you want extra caution . if you move the center clockspring wheel you must center it or you will tear it and get a light its 6 turns set at 3 turns fron end with finger steering wheel centered of course its unrepairable details on you tube