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Fec001
14th February, 2015, 07:24 PM
Hi!
I have a W204 here what has crashed and shot off airbags. Now all airbags and tensioners, pyrotechnik units changed to new. All ok, except passanger airbag stage1 and pyrotechnik lead for the battery. I checked the connections, the wires and tried to solder airbag directly without connector but "resistance too big" in measured values at passanger bag and battery lead. This could be some kind of new "crash data problem"??

Thanks for info!!!
FxShaw
14th February, 2015, 08:10 PM
Sounds weird but no that cant be crash data. measure resistance on the lead and pass bag. Only time I seen this is when wire is melted together and touching each other.
Fec001
14th February, 2015, 10:04 PM
Wires doesn't melted togehter. When connector plugged into SRS unit, the wires are separate. Tried to solder 3 ohm resistors but doesn't help. It always shows "resistance too big" what means wires are torn. But measured all wires from aribag connector to SRS unit connector.
smayer
14th February, 2015, 10:44 PM
SRS unit demaged
aeoner
15th February, 2015, 12:52 PM
Try to connect both wires together if control unit in good condition resistance status should be changed form ''resistance too big'' to ''resistance too low'' if nothing happens replace or repair SRS unit
FxShaw
15th February, 2015, 06:07 PM
I meant test the actually ohm on the pyro fuse and passenger bag...Ok simple..instead of 3ohm..unplug the plugs and try 2ohm.
Fec001
15th February, 2015, 07:16 PM
Try to connect both wires together if control unit in good condition resistance status should be changed form ''resistance too big'' to ''resistance too low'' if nothing happens replace or repair SRS unit

I tried that too. Tomorrow will check SRS unit unside
szkeptmen
16th February, 2015, 01:17 AM
Measuring circuit failure... Common problem.
Replace the Bosch integrated circuit ( Bosch 30559 - 44 TQFP) like in Toyota airbag modules made by TRW - (NS 150734-2)
Fec001
16th February, 2015, 09:00 AM
Thank you!
Fec001
18th February, 2015, 03:02 PM
SRS unit doesn't have Bosch 30559 IC. Only one 44 TQFP chip what is Atmel APACEATIC65V71.
szkeptmen
19th February, 2015, 01:04 AM
Maybe 30453 ???
Fec001
19th February, 2015, 08:14 AM
http://tapatalk.imageshack.com/v2/15/02/18/0bfa6112d360f0f979f1cede8171447a.jpghttp://tapatalk.imageshack.com/v2/15/02/18/1d6d6d5d0b664e91ac0cfc74fe12f7b9.jpg




no, the Atmel is the only one with 44 pin
Fec001
20th February, 2015, 01:31 PM
Tried to change the Atmel MCU from another airbag unit (Fiat 500). After change the DTCs gone, no any DTC but in measured values all = 0 Ohm. I think MCU has a basic flash or rom so can't be swapped from another brand