Operation

OPERATION

ACTIVE RESTRAINTS

The primary passenger restraints in this or any other vehicle are the standard equipment factory-installed seat belts and child restraint anchors. Seat belts and child restraint anchors are referred to as an active restraint because the occupants are required to physically fasten and properly adjust these restraints in order to benefit from them. See the Owner's Manual in the vehicle glove box on the features, use, and operation of all of the factory-installed active restraints.

PASSIVE RESTRAINTS





The driver/passenger airbags and the driver/passenger Seat Belt Tensioners (SBT) were designed to reduce the risk of an injury to the chest and head in the event of a head-on collision.

The side airbags were designed to protect primarily the upper body and also to help protect the head in the event of a side collision.

Malfunctions in the SRS system are indicated on the Instrument Cluster (IC) by the airbag warning indicator lamp.

SRS - AIRBAG WARNING INDICATOR





The SRS airbag warning indicator lamp indicates that the SRS is ready for operation. When no faults are present in the system, the airbag warning indicator illuminates when the ignition switch is turned to the ON or RUN position and then goes out after approximately six seconds.

An error or malfunction is indicated in the SRS by the airbag warning indicator not illuminating when the ignition switch is turned to the ON or RUN position or not going out after six seconds.

Errors and malfunctions not endangering occupant protection are indicated by the airbag warning indicator illuminating for approximately two minutes when the ignition switch is turned to the ON or RUN position.

Errors and malfunctions which may endanger the occupant are indicated by the airbag warning indicator illuminating continuously.

In the case of an error or a malfunction the entire system should be checked according to the diagnosis instructions. The active restraints ARE NOT affected by an error or a malfunction in the SRS and remain operational.

PASSENGER AIRBAG OFF INDICATOR LAMP

The passenger Airbag Off Indicator Lamp operates in conjunction with the Passenger Airbag On/Off Switch. When the switch is turned to either the On or the Off position, the switch position is communicated to the Passenger Seat Occupant Simulator. The Passenger Seat Occupant Simulator then translates the switch position into a signal that the Occupant Restraint Controller is capable of reading in order to switch the Passenger Airbag on or off depending upon the Switch position. The Passenger Airbag Off Indicator Lamp will stay illuminated as long as the Passenger Airbag On/Off Switch is in the Off position.

FRONT END MEDIUM-SEVERE HEAD ON COLLISION SRS OPERATION





Only the seat belt tensioners (SBT) are triggered.

The ORC registers medium-deceleration (stage-one threshold) due to a collision.

The triggering pulse is transferred only to the SBT squibs, because the restraint function of the seat belts in combination with the SBT is sufficient enough to effectively protect the vehicles passengers for this type of collision.

A check is made whether the seat belts are fastened. If a seat belt is not fastened and the stage one threshold is exceeded the driver and passenger airbags are triggered to provide protection for the front passengers.

FRONT END SEVERE HEAD-ON COLLISION SRS OPERATION





"Stage two threshold" The ORC recognizes the vehicles rapid deceleration due to a collision. The ORC routes the triggering pulse to the driver and passenger airbag squibs. At the same time the driver and passenger SBTs are also triggered.

REAR-END COLLISION SRS OPERATION





When the ORC registers sudden acceleration which exceeds the forward threshold value a check is made to determine which front seat belts are fastened. The ORC then activates only the SBTs which have fastened seat belts. The driver/passenger airbags are not activated unless a frontal collision which exceeds the stage two threshold is detected.

SIDE IMPACT COLLISION SRS OPERATION





When either the driver or passenger side impact side airbag sensor detects a sudden lateral acceleration which exceeds the lateral threshold value a signal is sent to the ORC. The ORC then deploys the appropriate side airbag.





The SRS electrical circuits are continuously monitored and controlled by a microprocessor and software contained within the Occupant Restraint Controller (ORC) (1). An airbag warning indicator lamp in the Instrument Cluster (IC) illuminates for about six seconds as a bulb test each time the ignition switch is turned to the On or Start positions. Following the bulb test, the airbag warning indicator lamp is turned On or Off by the ORC to indicate the status of the SRS. If the airbag warning indicator lamp comes on at any time other than during the bulb test, it indicates that there is a concern in the SRS electrical circuits. Such a problem may cause airbags to not deploy when required, or to deploy when not required.

Deployment of the driver and passenger airbags depends upon the angle and severity of an impact. Deployment is not based upon vehicle speed; rather, deployment is based upon the rate of deceleration as measured by the forces of gravity (G force). When an impact is severe enough, the microprocessor in the ORC signals the inflator of the appropriate airbag units to deploy their airbag cushions. The SBT is provided with a deployment signal by the ORC in conjunction with the driver and passenger airbags. During a frontal vehicle impact, the seat belts are used to restrain both the driver and the passenger in the proper position for an airbag deployment. The SBT removes the slack from the seat belts to provide further assurance that the driver and passenger are properly positioned and restrained for an airbag deployment.

Typically, the vehicle occupants recall more about the events preceding and following a collision than they do of an airbag deployment itself. This is because the airbag deployment and deflation occur so rapidly. In a typical 30 mile-per-hour (48 kilometer-per-hour) barrier impact, from the moment of impact until the airbags are fully inflated takes about 40 milliseconds. Within one to two seconds from the moment of impact, the airbags are almost entirely deflated. The times cited for these events are approximations, which apply only to a barrier impact at the given speed. Actual times will vary somewhat, depending upon the vehicle speed, impact angle, severity of the impact, and the type of collision.

When the ORC monitors a concern in any of the SRS circuits or components, including the SBT, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit and sends an electronic message to the IC via the CAN to illuminate the airbag warning indicator. Proper testing of the SRS components, CAN data bus, ORC signals, and DTC information requires the use of a DRBIII(R) scan tool. Refer to the appropriate diagnostic information.

See the Owners Manual in the vehicle glove box, regarding features, use, and operation of all of the factory-installed active restraints.