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2004 325ci
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Discussion Starter · #1 · (Edited)
This quicky bypass was created & posted by papu84 in 2011. it can be built in 10 minutes, & worked the first time for me.

Papu84 has it right. How happy I was to see the seat-belted Red tumor disappear from my dashboard.
On my Coupe I didn't need to code anything .. the light went out on the next start. But if you want to see its status, its available in INPA go to chasis, then Instrument, then AIRBAG. & you can see it & do a delete if your ride needs one.

BTW if you don't have the resistor or the Diode, Conversation me and I'll send you a couple. I drawer full. USA only please.

Note the E46 & E60 instructions are different



Motor vehicle Font Parallel Advertising Tire
 

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2001 E46 330i Sedan
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419 Posts
Without capacitor in parallel you will get ”unocuppied” status. I‘ve done numerous bench testing on this with Scope to see the output waveform. In summary, the resistor in series just to clear the seat mat break alarm, the resistor in parallel to clear the seat mat short alarm. You can confirm this with Pasoft also.
 

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2001 E46 330i Sedan
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419 Posts
second this. cheap and effective.
Be careful some of the ebay simulator just good for clearing codes...you really need to make sure the passenger seat status as well whether it’s “Occupied” or “Not Occupied” after installing the simulator, this will determine the passenger airbag will be deployed or not during collision. Refer to my post #6.
 

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2004 325ci
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Discussion Starter · #9 ·
Without capacitor in parallel you will get ”unocuppied” status. I‘ve done numerous bench testing on this with Scope to see the output waveform. In summary, the resistor in series just to clear the seat mat break alarm, the resistor in parallel to clear the seat mat short alarm. You can confirm this with Pasoft also.
Agreed. The bag won't deploy lacking the cap.

ZBi701 were you able to check to see if they are sending a square wave to the little black box. At 1st glance their little circuit makes no sense without a square wave coming from somewhere and doing something.

I bought a replacement seat with a working butt mat. It ohms out perfectly .. but my car (E46 coupe) rejects the mat .. which is why I borrowed the circuit from papu84.

I wonder if there is a resistance variance from pad to pad and I have to somehow "calibrate it".
The little bypass circuit works fine .. but sure I'd like to keep that bag
 

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2001 E46 330i Sedan
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419 Posts
Agreed. The bag won't deploy lacking the cap.

ZBi701 were you able to check to see if they are sending a square wave to the little black box. At 1st glance their little circuit makes no sense without a square wave coming from somewhere and doing something.
I was able to see how the output square wave going from the black/blue font box to the SRS module by varying the simulator resistor/cap/diode configuration and values Here are some screenshot.

Seat mat break waveform
Rectangle Font Technology Engineering Parallel


Seat Not Occupied waveform

Rectangle Output device Computer Font Line


Seat Occupied waveform
Rectangle Font Line Slope Engineering


Whatever simulator connected to the present black with blue font box, the output signal going to SRS module must be similar to these.
 

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2004 325ci
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1,439 Posts
Discussion Starter · #11 ·
Very interesting. I will revisit taht little circuit this week to see if anyone has the schem for it. I mapped it and think I still have it .. but its been a while. I recall after I saw it "they must be operating above and below some reference point. Thank you very much for there traces. I have 2 Fluke but one is in a different state at the moment, and I've got the crappy one with a dead backlight. so I couldn't see it well
 
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