Passenger Airbag Question

[severous01]

maybe a loose switch in the buckle, or on the weight sensor...

[CTScott]

Originally Posted by severous01

maybe a loose switch in the buckle, or on the weight sensor...

From experience reverse engineering the passenger occupancy ECU to build my bypass module for people with aftermarket seats, I can say that it's not a loose connector.

The passenger occupancy ECU polls the sensors and the passenger seat belt switch every 100ms. If any of the 4 weight sensors or the buckle switch don't respond, it shuts down and flashes the passenger airbag off light. It won't reset from that state until the ignition is cycled.

For it to have done what you saw, it had to have weighed her as being under the limit for arming the airbag. If she is fairly light and was shifting in the seat or you hit a pretty good bump I could see the system disarming and then rearming the airbag.

Did the passenger seatbelt light come on as well?

[RedStickHam]

Originally Posted by CTScott

From experience reverse engineering the passenger occupancy ECU to build my bypass module for people with aftermarket seats, I can say that it's not a loose connector.

The passenger occupancy ECU polls the sensors and the passenger seat belt switch every 100ms. If any of the 4 weight sensors or the buckle switch don't respond, it shuts down and flashes the passenger airbag off light. It won't reset from that state until the ignition is cycled.

For it to have done what you saw, it had to have weighed her as being under the limit for arming the airbag. If she is fairly light and was shifting in the seat or you hit a pretty good bump I could see the system disarming and then rearming the airbag.

Did the passenger seatbelt light come on as well?

The seatbelt light only came on when she unbuckled. She did shift around in her seat a little though. One other thing to note was I had stopped the car to empty our mailbox before she did the seatbelt thing, so perhaps it reset with the ignition being turned off and back on.

Thanks.

RedStickHam

[laer899]

I kind of have a similar problem. I got in my Yaris one day and I noticed the seat belt light was blinking but no sound and the light for passenger air bag off was lite up. There was no passenger in the seat. I have tried sitting in the seat and fastening the buckle to see if the light goes off but no luck. Any ideas or solutions would be appreciated. It's getting annoying.

[CTScott]

Originally Posted by laer899

I kind of have a similar problem. I got in my Yaris one day and I noticed the seat belt light was blinking but no sound and the light for passenger air bag off was lite up. There was no passenger in the seat. I have tried sitting in the seat and fastening the buckle to see if the light goes off but no luck. Any ideas or solutions would be appreciated. It's getting annoying.

You can make the SRS system flash the SRS light to tell you what the issue is. You jump the two terminals below on the OBD port (with the ignition off) and then turn the ignition on. The SRS light will then flash in a pattern to indicate the error. The pattern will groups of fast flashes, separated by longer off periods. If more than one DTC is logged, then the codes will be separated by even longer off periods.

[misolith]

I have a 2007 Yaris with a DTC 51 that according to other posts on this list indicate a problem in the Clock Spring.

I just replaced the clock spring with a new one and I found that there seems to have been a short in the spring on the cables with the black connector terminal on the end of the clock spring.

I've replaced everything and there's now no continuity on the cables in the the orange or the black terminals of the new clock spring.

I turned on the car and it still shows a DTC 51. I disconnected the battery and the DTC is still 51.

Have you any other advice as to how this error might be cleared?

Originally Posted by CTScott

You can make the SRS system flash the SRS light to tell you what the issue is. You jump the two terminals below on the OBD port (with the ignition off) and then turn the ignition on. The SRS light will then flash in a pattern to indicate the error. The pattern will groups of fast flashes, separated by longer off periods. If more than one DTC is logged, then the codes will be separated by even longer off periods.

[CTScott]

Originally Posted by misolith

I have a 2007 Yaris with a DTC 51 that according to other posts on this list indicate a problem in the Clock Spring.

I just replaced the clock spring with a new one and I found that there seems to have been a short in the spring on the cables with the black connector terminal on the end of the clock spring.

I've replaced everything and there's now no continuity on the cables in the the orange or the black terminals of the new clock spring.

I turned on the car and it still shows a DTC 51. I disconnected the battery and the DTC is still 51.

Have you any other advice as to how this error might be cleared?

See this thread for instructions on how to clear the DTC. With the SRS, codes like this will not clear by disconnecting the battery:

http://www.yarisworld.com/forums/sho...d=1#post557473