99 c70 passenger airbag problem

kwma01 · Post by **kwma01** » 13 Feb 2015, 06:22

I am having issues with the airbag light coming on for the passenger airbag. I have forgotten the code but it says that there is an open circuit. I have checked the wires and they are good all the way back to the SRS module. I have replaced the airbag with two others and still get the error. I have put 5ohms on the connector and the light goes out. Doesanyone have a suggestion on what could be going on?

Thanks
kwma01

Post by **cn90** » 13 Feb 2015, 07:06

Clear the codes to see if they come back.

Post by **abscate** » 13 Feb 2015, 09:16

I think you need a higher end scanner to clear a 1999 SRS code, or dealer assistance.

kwma01 · Post by **kwma01** » 13 Feb 2015, 11:35

I have a vida dice scanner and I have cleared the codes. It keeps coming back.
thanks

kwma01 · Post by **kwma01** » 16 Feb 2015, 15:55

I wanted to give an update on this issue. I have fixed the problem so that the light does not come on but I do not like the approach that i had to take. Sorry for being long winded.

I traced the wiring for the airbag back to the airbag module under the console. I used an ohm meter to check the wires between the module and the connector near the airbag. Everything seemed fine. I then took the wires out of the connector at the airbag module and swapped the driver side and passenger locations. This verified that the module was working correctly because the fault was now showing on the driver side. I corrected the wiring in the connector and started looking elswhere

The connector near the airbag connects to a short pigtail that plugs into the harness on one end and into the end of the airbag on the other. I put a 3 ohm resistor across the leads on the connector and rescanned with the dice scanner and everythring read good. I then hooked the 3 ohm resistor across the pigtail that I had removed from the end of the airbag. Now I had the problem again (SRS code 222 open circuit). As I stated before I have several airbags and therfore had multiple pigtails. I tried others with the same results. I then disected one of the pigtails to see that there is a capacitor inline with one of the leads. I assume that the airbag sends an AC signal to ignite the bags to go thru the capacitor. I found that I could run a 2 ohm resistor in parallel with the capacitor and my code would go away. It acted like the module could not communicate thru the capacitor and the resistor gave it an alternate communication path. I do not understand why things changed to cause this problem and I do not understand why I have the same issue with multiple airbags. I only know that my problem has gone away. Now I have to wonder if the bag will work if I am ever in a collision.

Any thoughts?

kwma01

Post by **abscate** » 17 Feb 2015, 09:50

yeeks. Be careful with ohmmeters on airbags - you are passing current through those airbags and I don't know what the threshold is to fire them.....

Without knowing the protocol of testing and firing I can't offer much on this...anyone else?

kwma01 · Post by **kwma01** » 17 Feb 2015, 14:43

I did not actually measure the resistance of the airbag just the leads and the pigtail that was removed from the airbag.

I would not recommend putting an ohm meter on an airbag. Sorry if anyone thought that I did that.

Thanks