Glossary of Terms and Definitions

AIR BAG
An inflatable cloth cushion designed to deploy in certain frontal crashes. It supplements the protection offered by the seat belt by distributing the impact load more evenly over the occupant's head and torso.

B+
Battery voltage, the voltage available at the battery at the time of the indicated measurement. With the key On and the engine not running, the system voltage will likely be between 12 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.

BULB CHECK
The seven flashes of the Air Bag Telltale whenever the ignition switch transitions from the LOCK position to the RUN or START positions. If no SIR malfunctions are detected the air bag telltale will remain Off during normal vehicle operation.

COIL ASSEMBLY
An assembly of current-carrying coils (two for SIR) 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.

CONTINUOUS MONITORING
Tests performed by the SDM on the SIR system every 100 milliseconds while Ignition 1 voltage is present at the SDM.

CURRENT CODES
Current DTCs are malfunctions that are presently being detected.

CURRENT SOURCE DIAGNOSTICS
Tests performed by the SDM where deployment loop voltages are measured within their respective voltage ranges. This test checks for proper resistance of the deployment loops and for proper operation of the driver and passenger current sources.

DATA LINK CONNECTOR (DLC)
Connector which is connected by wires to multiple on-board control modules allowing communication with an off-board Scan tool.

DEPLOY
To inflate the air bag.

DEPLOYMENT LOOP
The circuits which supply current to the inflator module to deploy the air bag.

DIAGNOSTIC TROUBLE CODE (DTC)
An alpha numerical designator used by the SDM to indicate specific SIR system malfunctions.

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

EEPROM
Electrically Erasable Programmable Read Only Memory. Memory which retains its contents when power is removed from the SDM.

HIGHER PRIORITY FAULT
Each diagnostic fault code is assigned a priority based on the detectability with other codes present. The priority corresponds to the detectability of the malfunction only, and does not relate to the criticality of the malfunction with respect to deployment or non-deployment under any given condition.

HISTORY CODES
History DTCs are malfunctions detected since last clearing of the SDM memory. History DTCs are stored in the SDMs memory, most history DTCs can be cleared using the Scan tool. Some history DTCs are latched and cannot be cleared.

IGNITION CYCLE
The voltage at the SDM Ignition 1 input, with ignition switch On, is greater than 9 Volts for at least 10 seconds before turning ignition switch Off.

IGNITION 1
A battery positive (B+) circuit which is only powered with the ignition switch in the RUN or START position.

INITIATOR
The electrical component inside the inflator module which, with sufficient current flow, starts the chemical reaction that inflates the air bag.

NORMAL OPERATING VOLTAGE RANGE
The voltage measured between the SDM Ignition 1 terminal and ground is between 8 and 16 Volts.

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

PORTABLE SCAN TOOL
An off-board computer used to read diagnostic information from on-board computers via a data link connector.

SDM
Sensing and Diagnostic Module which provides reserve energy to the deployment loops, deploys the air bag when required and performs diagnostic monitoring of all system components.

SERIAL DATA
Information representing the status of the queried system.

SIR
Supplemental Inflatable Restraint.

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

TURN-ON-TESTS
Tests which the SDM performs on the SIR system once during each ignition cycle immediately after Ignition 1 voltage is applied to the SDM and before "Continuous Monitoring."

VLR DELAY (VOLT LOOP RESERVE)
Charging of the VLR power supply is inhibited briefly during ignition turn On. This allows detection of certain malfunctions related to Ignition 1 voltage.