Q: What are the key components and maintenance procedures for the Supplemental Restraint System (SRS) in vehicles, including airbag modules, diagnostic units, and impact sensors on Nissan Rogue?
A: These models contain a Supplemental Restraint System (SRS) that is frequently referred to as an airbag that is meant to protect the driver and the passenger from severe injuries in case of a head-on collision; some models contain side impact airbags in the front and also the roof rail. Diagnostic control unit is mounted under the center console, also for each model there are diagnosed systems that are situated in the center console. Air bag modules are the compartment or casing that contains the air bag along with the inflater unit, where the inflater assembly is fastened to the rear of the housing chamber to release the gas and inflate the bag almost simultaneously as it receives an electrical impulse. This signal is transmitted by a spiral cable which is a basically a flat, ribbon like electrically conductive tap regardless the position of the steering wheel. Airbag modules are located in the steering wheel, above the glove compartment on the side of a passenger and in certain models in the seatbacks and along the roofrails. Diagnosis/sensor unit, which includes on-vehicle microcomputer and crash sensor, checks the operation of the system when the vehicle is started and the check is complete, "AIRBAG" light is briefly illuminated if everything is in order. In case of any default, the light extension persists to glow, suggesting the need for the hot services. The crash zone sensor is fixed on the radiator support; the side air bag sensors are in each car door "B" pillar. In regards to airbag deployment, there are impact sensors that need to be triggered; this closes an circuit towards the inflater. A self-diagnosis circuit is provided in the SRS unit, to inform the driver whether the system is okay or not; a light comes in the instrument panel when the ignition is on, and should go off after approximately the next five seconds if all is okay with the SRS unit, however if the light does not go off, or blinks this denotes that the car's SRS system needs to be checked by a mechanic. When working nearer to the SRS components, the system has to be off, steering wheel should be centrally positioned, the ignition must be turned to the LOCK position, the battery cables must be disconnected and the person also have to ground oneself for eliminating the static electricity. After the service of the airbag system, the latter can be put back into operation by connecting the required connectors, not having occupants in the car, and performing certain actions to check the proper functioning of the airbag warning lamp. The driver's air bag cover and part of the steering wheel may be unbolted to have a good view of the spiral cable, however the passenger's air bag can remain fixed onto the instrument panel even when it is being unbolted. Also, all models incorporate pyrotechnic units in the front seat belt retractor, which tightens the seat belts for the occupant to prepare for the collision; such a system means that disabling of the air bag system is required when working on or around the seats.