How to trace the fault in the wiring of the airbag circuit

If you are experiencing unresponsive driver side power seat controls and an SRS (Supplemental Restraint System) airbag warning message on your 2008 Volvo S40 2.4i, it could be caused by a few different issues, such as:

1. Faulty seat control module: The seat control module is responsible for controlling the power seat functions. If it is faulty, the seat controls may not work and the airbag warning message may appear.
2. Wiring issue: A damaged or corroded wire connection can cause the seat controls to become unresponsive and the airbag warning message to appear.
3. Sensors issue: The seat and airbag system rely on a variety of sensors to function properly. If any of these sensors are malfunctioning, it can cause the seat controls to become unresponsive and the airbag warning message to appear.
4. Airbag module: The airbag module is responsible for controlling the airbags in the vehicle. If it is faulty, the airbag warning message will appear.

It's best to have a professional technician diagnose the problem and recommend the appropriate course of action. Sometimes, the problem can be solved by replacing a faulty module, repairing or replacing damaged wiring or sensors, but in some cases the repair may be more complex.
It's important to note that the airbag warning light should be taken seriously and repaired as soon as possible, as it can indicate a problem with the airbag system that could affect the safety of the vehicle in case of a collision.

Has this vehicle been in an accident? Have you taken the steering wheel off?
If No, you'll need to get this sorted as soon as possible!! These refer to the Safety Electronics on your vehicle that control the steering wheel airbag and the seatbelt system.
The one referring to the 'Driver Frontal Stage' is the steering wheel airbag trigger, (makes it go off in an accident!), and the 'Seatbelt Pretensioner' pulls the block you plug the belt into back during an impact to tighten the belt against you.

the air bag light is telling you the system has failed/disabled to locate the problem you need to get the fault code out of the airbag control module using a obd code reader the norm cause is damaged wiring/bad connectors under the seats for the seat belt pretensioners disconnect the connectors and apply contact grease refit and retest

The warning light means that a fault has occurred in the Airbag system (known as the "SRS" system), when this light is on the SRS system is disabled, so no the Airbag can't go off because the controller module has turned it off completely. Get it fixed ASAP because right now if you have an accident your SRS system will not work (Airbags will not deploy) to save you from injury.

Take it to the dealership or you may purchase a scan tool with airbag test/reset kit.

Hi there:The Restraints Control Module (RCM / located behind right side of the instrument panel) monitors the resistance of the driver side air bag circuit loop and the air bag module igniter at RCM, if the resistance is greater than 3.6 ohms, the RCM will store diagnostic trouble code B1994 and flash lamp fault code.
About the possible causes, pay attention that a high resistance on the driver side air bag circuit can be caused by:

• - damaged wiring on circuit 1257 (WH/LB).
• - damaged wiring on circuit 1258 (BN/LB)
• - damaged driver side air bag module.
• - damaged RCM.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

{: ) It is possible, but not always the case. An airbag light on your instrument cluster may mean several things. Usually under normal conditions, an airbag light on warns the driver that the airbag system has detected a fault somewhere in the airbag circuits and need to be checked or fixed, otherwise the airbag protection system may not work properly in the event of collision. It can be wiring or component malfunctions.
Sometimes it can be a deployed component like the seat belt retractors or an SDM, which you may not notice. Your vehicle needs to be checked by a diagnostic scan tool for trouble codes. This way, you can easily determine the status of your airbag system.
If your vehicle did have an impact before that you're not aware of, and no attempts were made to have it repaired despite previous airbag light warnings, well, you can always expect the airbag light to come on.

its unfortunate but u are not able to. Your vehicle has multiple computers controlling all the electrics.
When a warning light comes on such as your airbag light or an engine light it is usually because of a fault.
if there is a fault and you ignore it and just cancel the light, then in an accident the airbag might not deploy. which would not be a good end result.
i would take it to a mechanic who has a scan tool to find the code that is causing your airbag light to come on, then fix the issue.
this will solve your airbag light problem and keep you safe on the roads as well.

cheers

The air bag control module self-checks the crash sensors every time the engine is started, so unless the air bag warning light is on the sensors are assumed to be okay. If a fault is detected, the air bag warning light will come on and usually deactivate the air bag system. Using a scan tool, you can pull the trouble code from the system and refer to the appropriate diagnostic chart in a service manual to troubleshoot the problem. Air bag service information can also be found on the vehicle manufacturer's website. Loss of circuit continuity anywhere in the air bag system, or loss of power to the air bag module are common causes of trouble codes.

Because crash sensors are sealed units, you cannot always determine their true condition by outward appearances. Any sensor that is obviously sustained physical damage as a result of a collision or other damage should be replaced. But what about ones that look okay? Most electromechanical crash sensors are designed to be electrically open in their rest condition. So one quick check you can perform is to check for continuity with an ohmmeter. If the sensor contacts are closed, it has not reset and should be replaced.

CAUTION! Do not attempt to check or replace any crash sensor unless the air bag module has first been deactivated (or deployed as a result of an accident). This can be done by unplugging the air bag connector at the base of the steering column and waiting at least 10 minutes or longer depending on the application (always refer to a service manual for the proper deactivation and removal procedure).

Hey there Henry,

Sorry to hear about your accident. Hope everyone is ok.
I worked at a wrecking yard where I pulled hundreds of airbags. I want you to understand, they can be dangerous if handled improperly.

Some warnings before you begin. Take these Seriously!!!

• Alway wear safety glasses.
• Control the environment - no kids, pets, people horsing around.
  
• Disconnect the negative battery terminal. After you are done, make sure no one is inside the vehicle when you reconnect the battery. If your vehicle has an anti-theft system, you'll need to get your activation codes to reset your sound system.
• Do not use solvents to clean your airbags. They may ignite if accidentally deployed. Use only a damp cloth.
  
• Airbags are sensitive to heat in excess of 190 degrees F. Store them accordingly.
  
• Airbags are sensitive to impact - handle them carefully
• Airbags are sensitive to static electricity - ground yourself, Spray the seat and rug with fabric softener (anti-static - ever heard the term 'static cling')
• Be safe

The procedures are pretty simple

Drivers Side:

• Disconnect the negative battery cable.
  
• Loosen and remove the retaining screws from behind the steering wheel. Rotate the wheel as needed to access the screws. You may need to purchase new retaining screws in advance to install the new bag.
  
• Return the wheel to the straight ahead position.
• Lift the airbag assembly out and disconnect the wiring connector from the rear of the unit.
• Unwrap the new airbag (carefully).
• Connect the the wiring connector and seat the airbag into the steering wheel. Be sure the wire doesn't get pinched.
• Install the new retaining screws and tighten them securely.
  

Passenger side:

• Loosen and remove the passenger side dash retaining screws
• Move it downward to release the retaining clips and remove.
• Unscrew the airbag retaining screws along the edge of the airbag.
• Move the airbag assembly downward the release it fom its mounting pegs.
• Remove the airbag from the dash, disconnecting the wire as soon as you are able. I believe your model has mounting guides, if so save them.
• If there were guides, place them back into the mounting frame.
• Position the airbag over the mounting frame and reconnect the wiring connector.
  
• Mount the new airbag, securely tighten the retaining screws.
• Remount the dash and screw it back in.
• Make sure nobody is in the car
• Reconnect the battery.

All done

One more time, be serious, be careful, be safe.

I hope this helps
Mike