Air Bag Terminology

AIR BAG - An inflatable cloth cushion designed to deploy in certain frontal crashes. It supplements the protection offered by the seat belts by distributing the impact load more evenly over the vehicle occupants head and torso.

ARMING SENSOR - A mechanical sensor on the high (power) side of the deployment loops. The arming sensor is calibrated to supply voltage to the inflator modules when the vehicles velocity changes are severe enough to warrant arming of the air bags in preparation for deployment. The arming sensor is located in the center sensor assembly.

ASYNCHRONOUS - Performed in a nonperiodic fashion, i.e., no defined time or interval.

BATTERY VOLTAGE (B+) - The voltage available at the battery at the time of indicated measurement. With the ignition switch ON and the engine not runing, B+ will likely be between 11.5 and 12.5 volts. At idle, the voltage may be 14 to 16 volts. The voltage could be as low as 10 volts during engine cranking.

CENTER SENSOR ASSEMBLY - Provides reserve energy to the deployment loops, performs diagnostic monitoring of all SRS components and contains the anning sensor and passenger compartment sensor.

CONSTANT CHECK - Tests performed by the center sensor assembly on the SRS while ignition or accessory voltage is present.

DATA LINK CONNECTOR (DLC) - A connector, which is connected by wires to multiple on-board computers, allowing communication with an off-board computer such as a scan tool. You jumper the DLC terminals to cause the center sensor assembly to enter the flash DTC mode. The center sensor assembly displays DTCs when in the flash DTC mode.

DATUM LINE - A base line parallel to the plane of the underbody or frame. All vertical measurements originate from the datum line.

DEPLOY - To inflate the air bag.

DEPLOYMENT LOOPS - The circuits which supply current to the inflator module to deploy the air bags.

DIAGNOSTIC TROUBLE CODE (DTC) - A numerical designator used by the center sensor assembly to indicate specific SRS malfunctions.

DRIVER INFLATOR MODULE - An assembly located in the center of the steering wheel, consisting of an inflatable bag and the inflator.

INITIATOR - The electrical component inside the inflator module which, when sufficient current flows, sets off the chemical reaction that inflates the air bag.

PASSENGER COMPARTMENT SENSOR - A semiconductor sensor on the low (ground) side of the deployment loops. The passenger compartment sensor is calibrated to ground the inflator modules when the vehicles velocity changes are severe enough to warrant deployment of the air bags. The passenger compartment sensor is located inside the center sensor assembly.

PASSENGER INFLATOR MODULE - An assembly located in the right side of the instrument panel consisting of an inflatable bag, an inflator and an initiator.

PRIMARY CHECK - Tests which the center sensor assembly performs on the SRS once during each ignition cycle immediately after ignition or accessory voltage is applied to the center sensor assembly.

SCAN TOOL - An off-board computer, such as a TECH 1, used to receive diagnostic information from on-board computers via the DLC.

SRS COIL ASSEMBLY - An assembly of current - carrying coils in the driver deployment loop that allows the rotation of the steering wheel while maintaining the continuous contact of the driver deployment loop to the driver inflator module.

12 to 16 VOLT RESERVE POWER SUPPLY - An energy supply in the center sensor assembly which provides deployment power when vehicle voltage is low or lost in a frontal crash.