Air Bag Systems: Service Precautions
Supplementary Restraint System (SRS) Precautions
The following precautions must be adhered to when working on the SRS system.
WARNING:
^ All components of the SRS must be replaced every 15 years.
^ Do not use rear facing child seats in the front passenger seat if the vehicle is fitted with a passenger airbag.
General Precautions
The SRS contains components which could be potentially hazardous to service personnel if not serviced and handled correctly. The following guidelines are intended to alert personnel to potential sources of danger and emphasise the importance of ensuring the integrity of SRS components fitted to the vehicle.
WARNING:
^ Always follow the 'SRS Precautions' and the correct procedures for working on SRS components. Persons working on SRS systems must be fully trained and have been issued with copies of the safety guidelines.
^ It is imperative that before any work is carried out on the SRS system, the appropriate information is read thoroughly.
^ The airbag modules contain extremely flammable and hazardous compounds. Contact with water, acids or heavy metals may produce harmful or explosive results. Do not dismantle, incinerate or bring into contact with electricity before the unit has been deployed.
^ Always replace a seat belt assembly that has withstood the strain of a severe vehicle impact or if the webbing shows signs of fraying.
^ Always disconnect the vehicle battery before carrying out any electric welding on a vehicle fitted with an SRS system.
CAUTION: Do not expose airbag modules or seat belt pre-tensioners to temperatures exceeding 85 degree C (185 degree F).
It should be noted that these precautions are not restricted to operations performed when servicing the SRS system. The same care should be exercised when working on ancillary systems and components located in the vicinity of SRS components; these include but are not limited to:
^ Steering system - Steering wheel airbag, rotary coupler
^ Front fascia - Passenger front airbag
^ Interior trim - Head airbag modules - front and rear
^ Seats - Front seat belt pre-tensioners
^ Electrical system - SRS harnesses, link leads and connectors
^ Front doors - Side (thorax) air bags
Making the system safe
Before working on or in the vicinity of SRS components, ensure the system is rendered safe by performing the following operations.
^ Remove the ignition key
^ Disconnect battery, earth lead first
^ Wait 10 minutes for the SRS power circuit to discharge before commencing work
The SRS uses energy reserve capacitors to keep the system active in the event of electrical supply failure under crash conditions. It is necessary to allow the capacitors sufficient time to discharge (10 minutes) in order to avoid the risk of accidental deployment.
Installation
In order to ensure system integrity, it is essential that the SRS system is regularly checked and maintained so that it is ready for effective operation in the event of a collision. Carefully inspect SRS components before installation. Do not install a part that shows signs of being dropped or improperly handled, such as dents, cracks or deformation.
WARNING: The integrity of the SRS systems is critical for safety reasons. Ensure the following precautions are always adhered to.
Do not fit accessories or other objects to trim panels (e.g. 'A' Post) which cover ITS airbags.
^ Never install used SRS components from another vehicle or attempt to repair an SRS component.
^ When repairing an SRS system, only use genuine new parts.
^ Never apply electrical power to an SRS component unless instructed to do so as part of an approved test procedure.
^ Special fixings are necessary for installing an airbag module - do not use other fixings and ensure that all fixings are tightened to the correct torque.
^ Always use new fixings when replacing an SRS component.
^ Ensure the SRS diagnostic control unit (DCU) is correctly installed. There must not be any gap between the DCU and the bracket to which it is mounted. An incorrectly mounted DCU could cause the system to malfunction.
CAUTION:
^ When fitting an head airbag module, ensure the securing clips are locked and do not trap the airbag. Take care not to trap the head airbag when fitting interior trim components e.g. 'A' post trim, headlining.
^ Ensure SRS components are not contaminated with oil, grease, detergent or water.
^ Torque wrenches should be checked regularly to ensure that all fixings are tightened to the correct torque.
NOTE:
^ Following seat belt pre-tensioner deployment, the seat belts can still be used as conventional seat belts, but will need to be replaced as soon as possible to establish full SRS protection.
^ If the SRS components are to be replaced, the part number/bar code of the new unit must be recorded.
SRS component testing precautions
The SRS components are triggered using relatively low operating currents, always adhere to the following precautions:
WARNING:
^ Do not use a multimeter or other general purpose test equipment on SRS system components or accidental deployment may occur. Use only Testbook/T4 to diagnose system faults.
^ Do not use electrical test equipment on the SRS harness while it is connected to any of the SRS system components, it may cause accidental deployment and personal injury.
Handling and storage
Observe the following precautions when handling SRS components.
WARNING: There are regulations for the storage of SRS components which must be observed, consult your local authority for details. The SRS components are sensitive and potentially hazardous if not handled correctly; always comply with the following handling precautions:
^ Never drop an SRS component. The airbag diagnostic control unit is a particularly shock sensitive device and must be handled with extreme care. Airbag modules and seat belt pre-tensioner units could deploy if subjected to a strong shock.
^ Never wrap your arms around an airbag module. If a module has to be carried, hold it by the cover with the cover uppermost and the base away from your body.
^ Never transport airbag modules or seat belt pre-tensioners in the cabin of a vehicle. Always use the luggage compartment of the vehicle for carrying airbag modules and seat belt pre-tensioner units.
WARNING:
^ Never attach anything to an airbag cover or any trim component covering an airbag module. Do not allow anything to rest on top of an airbag module.
^ Always keep components cool, dry and free from contamination.
CAUTION: Do not apply grease or cleaning solvents to seat belt pre-tensioner units, component failure could result.
WARNING:
^ Store the airbag module with the deployment side uppermost. If it is stored deployment side down, accidental deployment will propel the airbag module with sufficient force to cause serious injury.
^ Airbag modules and seat belt pre-tensioners are classed as explosive devices. For overnight and longer term storage, they must be stored in a secure steel cabinet which has been approved as suitable for the purpose and has been registered with the local authority.
^ Store the airbag module or seat belt pre-tensioner in a designated storage area. If there is no designated storage area available, store in the locked loadspace of the vehicle and inform the workshop supervisor.
CAUTION: Improper handling or storage can internally damage the airbag module making it inoperative. If you suspect the airbag module has been damaged, install a new module and refer to the deployment/disposal procedures for disposal of the damaged module.
WARNING:
^ Keep new inflatable tubular structure (ITS) airbag module in the original packaging until just prior to fitting. Place the old ITS module in the empty packaging for carriage.
^ When handling an inflatable tubular structure (ITS) airbag module, hold by the gas generator housing, DO NOT hold by the airbag. Do not wrap the thumb around the gas generator while holding. Do not drape airbag over shoulder or around neck.
For seat buckle type pre-tensioners, hold by the piston tube, with the open end of the piston tube pointing towards the ground and the buckle facing away from your body. Do not cover the end of the piston tube. DO NOT hold buckle type pre-tensioners by the bracket assembly or cable. Never point the piston tube towards your body or other people.
SRS harness and connectors
Always observe the following precautions with regards to SRS system electrical wiring:
CAUTION: Observe the following precautions:
^ Never attempt to modify, splice or repair SRS wiring.
^ Never install electrical equipment such as a mobile telephone, two-way radio or in-car entertainment system in such a way that it could generate electrical interference in the airbag harness. Seek specialist advice when installing such equipment.
NOTE: SRS wiring can be identified by a special yellow outer sleeve protecting the wires (black with yellow stripe protective coverings are sometimes used).
WARNING: Always ensure SRS wiring is routed correctly. Be careful to avoid trapping or pinching the SRS wiring. Do not leave the connectors hanging loose or allow SRS components to hang from their harnesses. Look for possible chafing points.
Side impact crash sensor inspection
After any degree of side body damage, inspect both side impact crash sensors. Replace a crash sensor if there is any sign of damage or deformation to the sensor fixings.
Ensure the side impact crash sensors are installed correctly. There must be no gap between the sensor and the mounting. Use either the fixings supplied with the replacement or new fixings and tighten to the correct torque.
CAUTION: Take extra care when painting or carrying out bodywork repairs in the vicinity of the crash sensors. Avoid direct exposure of the crash sensors or link harnesses to heat guns, welding or spraying equipment. Take care not to damage sensor or harness when refitting components.
Rotary coupler precautions
CAUTION: Always follow the procedure for fitting and checking the rotary coupler as instructed in the SRS repairs section. Comply with all safety and installation procedures to ensure the system functions correctly. Observe the following precautions:
^ Do not unlock and rotate the rotary coupler when it is removed from the vehicle.
^ Do not turn the road wheels when the rotary coupler is removed from the vehicle.
^ Always ensure the rotary coupler is removed and installed in its central position and with the front road wheels in the straight ahead position - refer to SRS for the correct removal and installation procedure.
^ If a new rotary coupler is being installed, ensure the locking tab holding the coupler's rotational position is not broken; units with a broken locking tab must not be used.
Airbag location labels
Airbag location labels are displayed at various positions in the vehicle. SRS components have additional warning labels displayed on them to indicate that particular care is needed when handling them. These include airbag modules, crash sensors, and seat belt pre-tensioners.
WARNING: It is imperative that before any work is undertaken on the SRS system, the appropriate information is read thoroughly.
NOTE: The following list indicates possible locations and content for warning labels. The exact positions and content may vary dependent on model year, legislation and market trends.
Passenger side fascia label
Driver/passenger door label
Steering wheel label
'A' Post label
Rotary coupler label - part no. location
The Land Rover part number must be recorded if an airbag module is to be replaced.
Always exercise caution when working with components, refer to the appropriate repair operation when replacing components; do not attempt to prise open or repair module case.
Modules contain high pressure gas and flammable material. To prevent personal injury, observe the following:
^ Do not repair, dismantle, incinerate or bring into contact with electricity (such as voltmeters).
^ Do not store in a place where temperature reaches 93 degree C (200 degree F) or higher.
^ Do not install components in another vehicle.
^ Do not install any foreign objects between airbag and its cover or within modules.
^ Service or dispose of components as directed in the appropriate repair operation.
Driver's airbag module label
Passenger's airbag module label
Bar codes or part numbers are attached to certain components which are critically related to correct operation. The number(s) must be recorded if the component is to be replaced.
Front head airbag module label
A label is attached to the airbag module identifying the need for caution and the importance of referring, before commencing work on the SRS components.
WARNING: The use of correct trim components is critical to the correct functioning of the airbag modules during deployment. Do not re-use SRS related interior trim components if they show signs of damage; always use new components.
VEHICLE RECOVERY
Towing - SRS components not deployed
Normal towing procedures are unlikely to cause an airbag to deploy. However, as a precaution, switch the ignition off and then disconnect both battery leads - negative (-) lead first.
Towing - SRS components deployed
Once the driver's airbag has been deployed, the vehicle must have a front suspended tow. However, as a precaution,switch the ignition off and then disconnect both battery leads - negative (-) lead first.
Airbag and pre-tensioner deployment
Deployment procedures and precautions as detailed in this should be strictly adhered to. Only personnel who have undergone the appropriate training should undertake deployment of airbag and pre-tensioner modules. The following precautions must be complied with:
^ Only use deployment equipment approved for the intended purpose.
^ Deployment of airbag / pre-tensioner modules should be performed in a well ventilated area which has been designated for the purpose.
^ Ensure airbag / pre-tensioner modules are not damaged or ruptured before attempting to deploy.
^ Notify the relevant authorities of intention to deploy airbag and pretensioner units.
^ When deploying airbag pre-tensioner units, ensure that all personnel are at least 15 meters 5 feet) away from the deployment zone.
^ Ensure deployment tool is connected correctly, in compliance with the instructions detailed in the SRS section. In particular, ensure deployment tool is NOT connected to battery supply before connecting to airbag module connector.
^ When deploying seat belt pre-tensioners, ensure pre-tensioner unit is secured correctly to the seat.
^ When removing deployed airbag modules and pre-tensioner units, wear protective clothing. Use gloves and seal deployed units in a plastic bag.
^ Following deployment of any component of the SRS system within the vehicle, all SRS components must be replaced.
^ DO NOT re-use or salvage any parts of the SRS system.
If a vehicle is to be scrapped, undeployed airbag modules and pre-tensioner units must be manually deployed. In this case airbags can be deployed in the vehicle; before deployment, ensure the airbag module is secure within its correct mounting position. Deployment of the driver's airbag in the vehicle may damage the steering wheel; if the vehicle is not being scrapped, deploy the module outside of the vehicle.
WARNING: During deployment parts of the airbag module become hot enough to burn you. Wait 30 minutes after deployment before touching the airbag module.