BMW4036

No, el que has marcado en rojo no.
Es el conector amarillo que has marcado en azul.
Hay que desconectarlo y medir la resistencia en los pines macho de ese conector que van a la batería. Recuerda aislar un pin de la placa metálica que se ve dentro del conector, y que los pone en cortocircuito.
Utiliza si puedes un polímetro digital (recuerda...escala de ohmios).

SPTR

Ojito con medir eso, porque haciéndolo puedes provocar su detonación.

Al igual que los airbag, nunca se deben medir con tester, por eso el conetor de estos va puenteado al sacarlo para que en caso de medirlo no le entre corriente dentro.

lewis

a todo, todo... NO!!

BMW4036

¿En serio?
Vaya flipe. Sólo con la corriente de un polímetro... me parece muy raro ya que se supone que el módulo de airbag debe medirlo durante el diagnóstico inicial al poner el contacto. Yo creo que la tensión de activación debe ser 12V, y como seguro que la resistencia es muy baja debe ser una corriente alta para provocar la incadescencia.
No obstante, por cuestiones de seguridad, y en vista de que pueda existir cierto riesgo (yo lo medí, pero claro el mio no funcionaba) recomiendo que no se haga esa prueba....no vaya a ser.
Gracias a todos, especialmente a lewis por su generosa disposición.

lewis

entonces lo miro o no??? que tengo el coche con la bateria desconectada!!

BMW4036

Lewis: Si fuera el mio lo mediría, especialmente con un polímetro digital, que utiliza microamperios para medir resistencias. Seguro que el modulo de airbag usa más corriente para diagnosticarlo, al igual que el DIS de bmw.
Pero entiende que no te pueda pedir a ti que lo mires.
Si te animas sólo puedo decirte "muchas gracias". En caso contrario lo entiendo perfectamente.
En cualquier caso: "muchas gracias".

BMW4036

Para mayor información sobre el tema, parece que medir los dispositivos pirotécnicos no los dispara: En el documento de BMW del TIS para medición de los pretensores pirotécnicos, informa a los técnicos de que utilizen el polímetro del DIS en la escala de ohmios. Concretamente la medida que se espera es entre 1 y 6 ohmios. Desgraciadamente no dice nada de la medida de la separación de polo de batería, aunque probablemente sería la misma medida.

BMW4036

Lo que os decía de medir con multimetro los dispositivos pirotécnicos.
Esto es concretamente para los pretensores de cinturón de seguridad:

BMW4036

Más información de BMW donde se miden directamente las unidades de airbag con un polímetro:
SRS Fault Codes - System 3
FAULT
CODE
EXPLANATION
TROUBLESHOOTING*
1
SRS Control Unit Error
The SRS control unit has failed its own internal diagnostic. This code is can also be set when
overcharging or low battery conditions occur. To verify failure: Delete fault stored in memory, operate
vehicle for 5 minutes. Test for fault codes. If the fault recurs, the SRS Control Unit will need replacement.
2
Airbag Ignition Circuit - Drivers Side - Defective
This fault is often stored during repair of other components (removal of steering wheel or instrument
cluster). Disconnect connector from generator module. Check wires from control unit pin 10 to contact
ring pin 1 and pin 11 to contact ring pin 2 for continuity. Measure resistance of squib (detonator) at
generator module (1.8 - 5.6 ohms). Replace if out of range. Check steering-wheel contact ring. Connect
generator module and measure resistance at control-unit plug between pin 10 and pin 11 (1.8 - 5.6
ohms). Replace steering-wheel contact ring. If the fault code recurs, replace control unit.
3
Seatbelt Tensioning System Firing Circuit - Driver Side
Disconnect plug connection between seat wiring harness and vehicle wiring harness. Measure resistance
between pins 9 and 10 (seat side) (1.8 - 5.6 ohms). Disconnect plug-in connection to gas generator.
Measure continuity from firing generator connection pin 1, to plug, seat connection pin 9 and from firing
generator connection pin 2, to plug, seat connection pin 10. If ok, replace the gas generator of the driver's
seat-belt tensioner.
Disconnect plug-in connection from airbag control module. Check continuity of pin 1, to plug seat - vehicle
wiring harness connection pin 9 and from airbag control module, pin 2, to plug seat - vehicle wiring
harness connection pin 10.
Visually inspect the wires and plug-in connections.
Measure resistance at plug-in connection of driver's seat (control-unit side) between pin 6 and pin 7
(value < 1 ohm)
Measure voltage between pin 9 (seat side) and terminal 31 (ground).
Measure voltage between pin 10 (seat side) and terminal 31 (ground).
Try replacing the gas generator of the driver's seat-belt tensioner. Measure voltage between pin 1 (seat
end) and terminal 31 (ground). Measure voltage at plug-in connection of driver's seat (control-unit end) betw
Now clear fault memory. Read fault memory again. Fit together plug-in connection between seat wiring harn
- Measure voltage between pin 1 and terminal 31 (ground).
- Measure voltage between pin 2 and terminal 31 (ground).
- Measure resistance between pin 9 (seat side) and term. 31 (ground).
- Measure resistance between pin 10 (seat side) and term. 31 (ground).
- Measure resistance between pin 1 and terminal 31 (ground).
- Measure resistance between pin 2 and terminal 31 (ground).
Page 2
4
Seatbelt Tensioning System Firing Circuit - Passenger
Side
Measure the resistance between pin 3 and pin 4 from airbag control module.
Airbag control module pin 3, to plug seat - vehicle wiring harness, pin 6.
Airbag control module, pin 4, to plug seat - vehicle wiring harness, pin 7.
Try replacing the gas generator of the passenger's seat-belt tensioner.
Measure voltage between pin 13 and terminal 31 (ground).
Measure voltage between pin 14 and terminal 31 (ground).
Measure resistance between pin 13 and terminal 31 (vehicle ground).
Measure resistance between pin 14 and terminal 31 (ground).
5
Airbag Ignition Circuit - Passenger Side - Defective
Measure resistance between pin 13 and pin 14 (1.8 - 5.6 ohms).
- Pull apart plug-in connection between gas generator of passenger's airbag and vehicle wiring harness.
- Measure resistance between pin 1 and pin 2 at plug-in connection of the gas generator (wiring-harness
side).
- Check continutity between airbag control unit pin 13 to gas generator of passenger's airbag pin 1.
- Check continutity between airbag control unit pin 14 to gas generator of passenger's airbag pin 2.
- Pull apart plug-in connection to gas generator of passenger's airbag.
- Measure resistance at adapter for airbag control unit between pin 13 and pin 14.
- Measure resistance between pin 13 and terminal 31 (ground).
- Measure resistance in wire to airbag control unit between pin 1 and terminal 31 (ground).
- Measure voltage between pin 13 and terminal 31 (ground).
- Measure voltage in wire to airbag control unit between pin 1 and terminal 31 (ground). Specified value:
approx. 0 V
6-7
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
12-16
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
17
Power Supply
Check Battery and Charging System. Check supply voltage at the airbag control unit.
18
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
Page 3
19
SRS Warning Lamp Faulty
Does the warning lamp come on in ignition-lock position 1 and go out after approx. 4 seconds? If so then
the warning lamp is OK.
Warning lamp does not come on.
- Check continuity from airbag control unit pin 7 to instrument cluster (display unit) pin 13 and from
instrument cluster (display unit) pin 14 to terminal R.
- Connect pin 14 of the display unit to term. 30 AND Connect pin 13 of display unit to term. 31 (ground). If
the lamp does not illuminate, replace display unit of the instrument cluster (not instrument-cluster
electronics (IKE)).
The warning lamp does not go out if:
- A fault in the system is stored.
- The airbag control unit has not been coded. Code the control unit.
20
Seat Occupancy Detection Circuit - Passenger Side
Check continuity of seat occupancy electronics pin 3 to airbag control unit pin 15 and seat electronics Pin
2 to ground.
21
Pressure Sensor - Driver Side
22
Pressure Sensor - Passenger Side
23
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
24
Seatbelt Lock - Driver Side
Pull apart plug-in connection X 10214 to driver-seat section of wiring harness. Measure resistance at side
of seat between pin 2 and pin 3. Buckled 90 - 110 ohms, Unbuckled 360 - 440 ohms.
Driver's buckle switch is O.K.
- Pull apart plug-in connection X 778 to driver's seat-belt lock.
Note: possible only after removing components of seat. Follow Repair Manual.
- Check driver's buckle switch.
Measure resistance between pin 3 and pin 1. Replace driver's seat-belt lock. Check and repair if
necessary:
- Wire from driver's buckle switch X 778, pin 3, to plug connection on driver's seat X 10214, pin 2.
- Wire from driver's buckle switch X 778, pin 1, to plug connection on driver's seat X 10214, pin 3.
- Wire from driver's seat plug-in connection X 10214 pin 3 to airbag control unit pin 12.- From terminal 31
to driver's seat
plug-in connection X 10214 pin 3.
Repair wire.
Page 4
25
Seatbelt Lock - Passenger Side
SEAT-BELT LOCK, PASSENGER
- Measure resistance between connector pin 8
and terminal 31 (earth).
- Pull apart plug-in connection X 10215 to passenger-seat section of wiring harness.
Passenger's seat-belt lock is OK.
- Disconnect plug connection X 18165
to passenger's buckle switch.
Important: only possible after removal
of seat. Follow Repair Manual.
- Check passenger's buckle switch.
Replace passenger's seat-belt lock.
- Wire from passenger's buckle switch X 18165,
pin 3, to plug connection on driver's seat
X 10215, pin 2.
- Wire from passenger's buckle switch X 18165,
pin 1, to plug connection on driver's seat
X 10215, pin 3.
- From terminal 31 to passenger's seat
plug-in connection X 10215 pin 3.
- Wire from passenger's seat plug-in connection
X 10215 pin 3 to airbag control unit pin 8.
48-63
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
65
SRS Control Unit Internal Defect
(See Fault Code 76-77.)
67-72
SRS Control Unit Internal Defect
(See Fault Code 76-77.).
73
Airbag Squib wires - Short Circuited
Check wires to pins 1, 2, 3, 4, 10, 11, 13, and 14 for short-circuiting to each other.
76-77
SRS Control Unit Internal Defect
The SRS control unit has failed its own internal diagnostic. This code is can also be set when
overcharging or low battery conditions occur. To verify failure: Delete fault stored in memory, operate
vehicle for 5 minutes. Test for fault codes. If the fault recurs, the SRS Control Unit will need replacement.
The airbag control module may only be installed, removed
or disconnected when the BATTERY IS DISCONNECTED!
Under no circumstances disconnect, connect or move
ZAE/BAE control module while ignition is turned on!
Carry out repairs while battery is disconnected!

lewis

bueno, vamos a ver que se puede hacer....

Mañana me acerco al desguace que habia un par de e39, un 38 y me parece que algun 46 y miro a ver si tienen el cable dichoso y lo miro alli no sea que pase algo....

mañana te cuento.

saludos

SPTR

Puede que no pete por usar el tester, pero cuando yo estudiaba cosas de estas, los airbag si que llevaban en los conectores un sistema que al desconectarlos, se puenteaban esos para que si lo medias con el tester no entrara corriente dentro. Además se advertía que no se debía usar esos aparatos.

El polímetro del DIS = está diseñado para eso. No lo sé hasta que punto pero...

Los pretensores pirotécnicos tambien llevaban ese sistema en el conector, de protección contra curiosos del tester.

Ten en cuenta que seguramente los airbags y demás cosas pirotécnicas deberian detonar con poca corriente, por si revienta la bateria con el golpe, poder detonar con corriente almacenada en centralita airbag.

BMW4036

Bien. Finalmente, después de buscar información por todos los lados posibles he llegado a la conclusión de que todos los elementos del sistema de seguridad SRS (airbags, pretensores...) funcionan con valores de resistencia de entre 1 y 6 ohmios aprox.
Por tanto, he probado con una resistencia de 3,3 ohmios y arreglado.
En breve publicaré un brico de como saltarse la comprobación incial del sistemas de airbag válido para airbags, pretensores y bornes defectuosos.
Gracias a todos los que han colaborado: Lewis por su magnífica disposición y SPTR por sus advertencias de seguridad.
NOTA: Los sistemas de seguridad deben permanecer activos y funcionando siempre. No se debe engañar al sistema de comprobación salvo justificación (por ejemplo que ese sistema de seguridad se haya demostrado ineficaz y se haya dejado de fabricar, como es el caso).

Saludos.