The crash safety module (ACSM) has the following tasks:
The following components are described for the crash safety module:
All inflator assemblies and sensors are connected directly to the ACSM control module.
The ACSM control module evaluates the data from the sensors.
In the event of a collision, the ACSM control module decides whether seat belt tensioner and airbag triggering is required and which airbags have to be triggered.
Two acceleration sensors are fitted in the ACSM control module.
The longitudinal acceleration sensor detects a frontal or rear-end collision.
The lateral-acceleration sensor detects a side-on collision.
An ignition capacitor is fitted in the ACSM control module. If the power supply is interrupted in a collision, the ignition capacitor serves as an energy reserve for the ACSM control module.
The airbag warning lamp indicates the proper functioning of the crash safety module. The airbag warning lamp in the instrument cluster is activated by the ACSM control module via the K-CAN.
The seat belt warning lamp is the visual seat belt warning. The visual seat belt warning tells the occupants to fasten their seat belts. The visual seat belt warning is started as of terminal 15 On.
The visual seat belt warning is displayed as follows:
If the indicator lamp for passenger airbag deactivation (passenger airbag off- lamp) lights up, the following airbags on the passenger's side are disabled: Front passenger's airbag and side airbag.
The passenger airbag off lamp is continuously monitored via the ACSM control module. A fault in the power supply or a defective lamp is saved in the fault memory of ACSM control module. In this case, the airbag warning lamp is switched on.
Depending on the severity of the accident, the flow of fuel is also interrupted. The DME or DDE switches the electric fuel pump off.
In the event of a rollover, the roll bar extends, locks and thus secures the survival space for the vehicle occupants. There is a roll bar behind each of the rear seats. In the event of an accident with rollover, the sensor in the vehicle center satellite detects the vibration and sends the information ”activate roll bar” to the safety module. The information ”activate roll bar” is forwarded across the serial cable. In addition, the other satellites determine the severity of the accident. With the information ”activate roll bar” matching ”severity of the accident”, the roll bars are triggered. There are two possibilities to activate the roll bar: Triggering in the event of an accident Triggering for verification of function via the diagnosis (service functions)
The following general data is provided for servicing the ACSM:
Disconnecting the battery terminals
Caution: After disconnecting the battery terminals, wait 1 minute before starting work on the ACSM safety system.
After disconnecting the battery terminals, 1 minute must be waited before starting work on the ACSM safety system.
The waiting period ensures that the capacitors with the energy reserve of the system are completely discharged. This prevents inadvertent triggering of airbags or seat belt tensioners.
Checking components of the crash safety module
Caution: Do not test components of the safety system with multimeters or other universal test devices.
Testing with a multimeter or other universal test tools can lead to accidental deployment and injuries. For system diagnosis, use only the BMW diagnosis system.
Caution: Do not connect any electrical test devices to the wire harness of the crash safety module.
Do not connect any electrical test devices to the wire harness of the crash safety module as long as the wire harness is connected to a component of the safety system. Accidental deployment and violation can occur.
Use exclusively the BMW diagnosis system for system diagnosis.
Caution: Check the ACSM safety system after repairing damage caused by an accident.
After repairing damage caused by an accident, the ACSM safety system must be checked using the BMW diagnosis system (even if this accident did not trigger a restraint system).
Fitting approved seat covers
Caution: only fit approved seat covers.
Do not fit seat covers, cushions or other objects on the front seats that have not been specially approved for seats with integrated side airbags. Do not hang articles of clothing, e.g. jackets, over the front seat backrests. This severely impairs or disables the airbag function.
Note: After 3 crash signals with triggering of the safety system, replace the ACSM control module.
The ACSM control module saves data in a non-erasable memory after a triggering of the safety system. After 3 crash signals, the data memory is full. The airbag warning lamp lights up. The ACSM control module must be replaced.
Note: Deactivating the acoustic seat belt warning
The acoustic seat belt warning can be disabled by means of encoding. This does not affect a legally prescribed seat belt warning.