Component Definitions

AIR BAG
An inflatable cloth cushion designed to deploy in certain frontal or side impact crashes. The air bags distribute the impact load more evenly over the occupant's head and torso in order to supplement the safety belt protection.

ASYNCHRONOUS
An event that can occur at any time without a warning and without falling within a defined time period.

B+
The battery voltage available at the time of the indicated measurement. With the ignition in ON and the engine stopped, the voltage is usually 11.5-12.5 V.With the engine at idle, the voltage may be 14.0-16.0 V. During engine cranking, the voltage can be as low as 10.0 V.

BULB TEST
The Instrument Panel Cluster (IPC) will flash the air bag warning lamp indicator 7 times when the ignition switch is turned from OFF to ON. The inflatable restraint Sensing and Diagnostic Module (SDM) then commands the IPC to turn the warning indicator OFF through serial data communication. This indicates that there are no malfunctions in the SIR system. If a SIR system malfunction is present, the IPC flashes the warning indicator seven times and the SDM then commands the IPC to turn the warning lamp indicator ON. An IPC malfunction could prevent the IPC from flashing the indicator.

CLASS 2
A serial data communications protocol.

CONTINUOUS MONITORING TESTS
The inflatable restraint Sensing and Diagnostic Module (SDM) continuously monitors the SIR system during each 60 millisecond interval. The IGNITION voltage at the module must be within the normal operating voltage range for the continuous monitoring to occur. These tests follow the power-on tests.

DATA LINK CONNECTOR (DLC)
The DLC electrically connects to many on-board computers and allows communication with an off-board computer such as a scan tool.

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

DEPLOY
To inflate the air bag.

DEPLOYMENT LOOPS
The circuits that supply the current to the inflator modules for air bag deployment.

DEPLOYMENT LOOP VOLTAGE OUT OF RANGE
This test is run during power-on and continuous monitoring diagnostics. The inflatable restraint Sensing and Diagnostic Module (SDM) performs this test in order to inspect for a short circuit to B+ or ground within the deployment loops. If the SDM detects a short circuit to voltage within a deployment loop, the resistance measurement test for that deployment loop will be not be run.

Deployment Loop Resistance Measurement Test
This test is run during power-on and continuous monitoring diagnostics. The inflatable restraint Sensing and Diagnostic Module (SDM) performs this test in order to inspect for proper deployment loop resistance. This test is run after the voltage out of range test as long as a short to B+ does not exist within the deployment loop.

DIAGNOSTIC TROUBLE CODE (DTC)
An alphanumeric designator used by the inflatable restraint Sensing and Diagnostic Module (SDM) in order to indicate specific SIR system malfunctions.

EEPROM (ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY)
Memory that does not require power to the inflatable restraint Sensing and Diagnostic Module (SDM) in order to retain its contents.

HIGHER PRIORITY FAULT
Each DTC has an assigned priority based on its detectability with other DTCs present. The priority corresponds to the detectability of the malfunction only. This does not relate to the seriousness of the malfunction with respect to deployment or non deployment under any given condition.

IGNITION CYCLE
The operation of the ignition switch causes this cycle to occur. The inflatable restraint Sensing and Diagnostic Module (SDM) must first sense IGNITION 1 input greater than 9.0 V with the ignition switch in RUN. The IGNITION 1 input voltage must remain above 9.0 V for at least 10 seconds before turning the ignition switch to OFF.

INFLATABLE RESTRAINT SENSING AND DIAGNOSTIC MODULE (SDM)
The SIR control module that provides reserve energy to the deployment loops, deploys the air bags when required, and performs diagnostic monitoring of all SIR system components.

INFLATABLE RESTRAINT IP MODULE
An assembly located on the IP consisting of an inflatable air bag, an inflator, and an initiator.

INFLATABLE RESTRAINT STEERING WHEEL MODULE
An assembly located in the steering wheel hub consisting of an inflatable bag, an inflator, and an initiator.

INFLATABLE RESTRAINT STEERING WHEEL MODULE COIL
An assembly of two or more current carrying coils mounted within the steering column hub. The assembly allows the rotation of the steering wheel while maintaining continuous electrical circuit contact. Two of the coils provide continuous contact of the driver deployment loop to the inflatable restraint steering wheel module.

INFLATABLE RESTRAINT SIDE IMPACT SENSOR (SIS)
The SIS is a discriminating sensor use as an input to the SDM to monitor the vehicle side accelerations/ decelerations to determine in a crash event which requires side airbag protection is needed. The SDM module provides reserve energy to the deployment loops, deploys the air bags when required.

INFLATABLE RESTRAINT SIDE IMPACT INFLATOR MODULES
An assembly located on the outboard sides of the front seat backs consisting of an air bag, an inflator and an initiator.

INFLATABLE RESTRAINT REAR SIDE IMPACT INFLATOR MODULES (W/AW9 OPTION)
An assembly located behind rear seat back consisting of an air bag, an inflator and an initiator.

INITIATOR
Located in the inflator module, the initiator initiates the chemical reaction that inflates the air bag when sufficient current flows through the component.

NORMAL OPERATING VOLTAGE RANGE
9.0-16.0 V when measuring between the inflatable restraint Sensing and Diagnostic Module (SDM) IGNITION POSITIVE VOLTAGE terminal and ground.

POWER-ON TESTS
Tests that the inflatable restraint Sensing and Diagnostic Module (SDM) performs on the SIR system once per ignition cycle. These tests occur immediately after the module receives IGNITION 1 voltage, and before the continuous monitoring tests.

SCAN TOOL
An off-board computer that reads on-board computer diagnostic information through the use of a DLC.

SEAT BELT BUCKLE PRETENSIONER
A pyrotechnic device located in the seat belt buckle consisting of a routing cable with piston, a piston tube, and a gas generator. When the seat belt buckle pretensioner deploys, its shortens the buckle height.

SERIAL DATA
The information communicated to an off-board computer using the DLC. Some of this data represents the status of the SIR system.

SIR
Supplemental Inflatable Restraint.

SIR WIRING HARNESS
The wires and connectors that electrically connect the components in the SIR system.

SOH
State Of Health

23 VLR
The 23 volt loop reserve. The energy supply that is internal to the inflatable restraint Sensing and Diagnostic Module (SDM).