Transistor switching and the SRS light

[shogun]

all 20 pin plugs have the same setup
http://www.autoshoppingcenter.com/se...ights/Bmw.html

[Kibokojoe]

Based on my schematic
Pin 12 is G2 Alternator, A2 Instrument cluster and A7 ABS control unit

Pin 16 is M201 Meter box, A17 Servotronic control unit and fuse 28

[shogun]

what you are now studying is not the diagnosis box, that is X20 or X21 as it is called for the M70 engine, that are the one or 2 (depending on engine type) besides the diagnostic box. And on my M70 engine they have 25 pins in total, not 20 as the diagnosis box.

[Kibokojoe]

My data is coming from a e34 pdf that is a 1989 535i Electrical troubleshooting manual. Based on "Tester command entering 315 will activate the transistorized switch"



I figure you could do the same with the SRS circuit



Specifically the transistor marked with the red arrow. I am sure that the transistor highlighted is generic but it is a transistor circuit/switch none the less. When the transistor is shorted to ground the SRS lights come on and when the transistor is activated through the "base" the lights will will go out

what you are now studying is not the diagnosis box, that is X20 or X21 as it is called for the M70 engine, that are the one or 2 (depending on engine type) besides the diagnostic box. And on my M70 engine they have 25 pins in total, not 20 as the diagnosis box.

[shogun]

I do not know the details, they are made in Germany and I just sell them, as many people are asking for a SRS reset tool which also works on older BMWs from 1987 -...

So I started importing them and many indy shops want them especially or also for private use. In addition it also incorporates besides the SRS reset the oil/inspection and annual inspection sign reset (annual clock sign only where applicable, depending by country version), but it does not read faults, just resets the warning lights when the fault has been repaired.

Peake does not have this, see here a copy from their website:

Airbag (SRS) Scan/Reset Tools for BMWs 1994-2003:
Reads all SRS fault codes, resets SRS Light!
R5/SRS (plugs in under hood)

R5/SRS-16 (plugs in under dash) R5/SRS-U (plugs in under dash and under hood)
R5/SRS Features:
Models available for most BMWs built between 1994 and 2003 Compatibility notes.
Displays all SRS fault codes, tells you what's wrong.
Resets the "SRS" Light.
Very easy to use
Low cost ($129.99)

[Ross]

Any update on this project??

[Kibokojoe]

Nothing so far. It looks like I will need to purchase Shoguns gizmo and try from that end. Can't find any documentation on the module. Frustrating

[whiskychaser]

I'd guess one of the chips on the board has received a signal causing it to 'latch'- ie it wont reset without the proper signal. If you can see the chip numbers on the board you may be able get a pinout and find what they do. That said, I'm a little uncomfortable about you turning a light out if the result is your airbag doesnt work when you need it