OPERATION
The multistage Driver AirBag (DAB) and active vent tether cutter are deployed by electrical signals generated by the Occupant Restraint Controller (ORC) through the DAB squib 1, 2 and 3 circuits to the two initiators in the airbag inflator and the tether cutter. By using two initiators and an active vent, the airbag can be deployed at multiple levels of force. The force level is managed by the ORC to suit the monitored impact conditions by providing one of several delay intervals between the electrical signals provided to the two initiators. The longer the delay between the initiator signals, the less forcefully the airbag will deploy.
When the ORC sends the proper electrical signals to each inflator initiator, the electrical energy generates enough heat to initiate a small pyrotechnic charge which ignites chemical pellets within the inflator. Once ignited, these chemical pellets burn rapidly and produce a large quantity of inert gas. The inflator is sealed to the back of the DAB housing and a diffuser in the inflator directs all of the inert gas into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the DAB trim cover will split at predetermined breakout lines, then fold back out of the way. Following a deployment, the airbag cushion quickly deflates by venting the inert gas towards the instrument panel through vent holes within the fabric used to construct the back (steering wheel side) panel of the airbag cushion.
The ORC is capable of additional DAB deployment force management by activating, suppressing and controlling the timing of the tether cutter to manage the active vent. The active vent flap internal to the DAB cushion is attached by a tether to the tether cutter. The ORC signals a small pyrotechnic charge within the tether cutter to control if and when the active vent tether will be cut. Whether and when the DAB vent flap is activated also influences DAB cushion deployment force by retaining or releasing the inert gas produced by the DAB inflator within the cushion.
Some of the chemicals used to create the inert gas may be considered hazardous while in their solid state before they are burned, but they are securely sealed within the airbag inflator. Typically, both initiators are used and all potentially hazardous chemicals are burned during an airbag deployment event. However, it is possible for only one initiator to be used during a deployment due to a Supplemental Restraint System (SRS) fault; therefore, it is necessary to always confirm that both initiators have been used in order to avoid the improper disposal of potentially live pyrotechnic or hazardous materials. Refer to STANDARD PROCEDURE .
The inert gas that is produced when the chemicals are burned during a deployment is harmless. However, a small amount of residue from the burned chemicals may cause some temporary discomfort if it contacts the skin, eyes or breathing passages. If skin or eye irritation is noted, rinse the affected area with plenty of cool, clean water. If breathing passages are irritated, move to another area where there is plenty of clean, fresh air to breath. If the irritation is not alleviated by these actions, contact a physician.
The ORC monitors the condition of the DAB through circuit resistance, and will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the DAB inflator and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
The Knee AirBags (KAB) (also known as Inflatable Knee Blockers/IKB) are deployed by electrical signals generated by the Occupant Restraint Controller (ORC) to which it is connected through a driver or passenger KAB line 1 (or squib) circuit to the initiator in the airbag inflator. The hybrid-type inflator assembly for each airbag contains a small canister of highly compressed inert gas. When the ORC sends the proper electrical signal to the airbag inflator, the electrical energy creates enough heat to ignite chemical pellets within the inflator.
Once ignited, these chemical pellets burn rapidly and produce the pressure necessary to rupture a containment disk in the inert gas canister. The inflator is sealed to the airbag cushion and a diffuser in the inflator directs all of the inert gas into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the KAB protective cover will split at predetermined tear seam lines concealed on the underside of the cover, then fold open and out of the way.
The cushion protects the lower extremities of the vehicle driver or front seat passenger and helps to keep the seat occupant properly positioned for the Driver AirBag (DAB) or Passenger AirBag (PAB) deployment during a frontal impact collision. Following an airbag deployment, the KAB cushion quickly deflates by venting the inert gas through the loose weave of the fabric used to construct the instrument panel side of the airbag cushion, and the deflated cushion hangs down loosely from the lower instrument panel.
The ORC monitors the condition of the KAB through circuit resistance, and will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the KAB initiators and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
The multistage Passenger AirBag (PAB) is deployed by electrical signals generated by the Occupant Restraint Controller (ORC) through PAB squib 1 and squib 2 circuits to the two initiators in the airbag inflator, and by a PAB squib 3 circuit to the active vent tether release. By using two initiators and an active vent, the PAB can be deployed at multiple levels of force. The force level is managed by the ORC to suit the monitored impact conditions by providing one of multiple delay intervals between the electrical signals provided to the two initiators and the tether release. The longer the delay between the initiator signals and the sooner the active vent tether is released, the less forcefully the PAB will deploy.
When the ORC sends the proper electrical signals to each initiator, the electrical energy generates enough heat to initiate a small pyrotechnic charge which, in turn ignites chemical pellets within the inflator. Once ignited, these chemical pellets burn rapidly and produce a large quantity of inert gas. The inflator is sealed to the airbag cushion and a diffuser in the inflator directs all of the inert gas into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the PAB door will split at predetermined tear seam lines concealed on the inside surface of the door, then the door will pivot up over the top of the instrument panel and out of the way. Following an airbag deployment, the airbag cushion quickly deflates by venting the inert gas through a discrete vent in each fabric side panel of the airbag cushion.
The tether release unit controls a normally closed active vent flap in the cushion. The ORC monitors a seat track position sensor on the passenger front seat. If the seat is in the full forward position when an airbag deployment occurs, the ORC signals the tether release to release the tether that normally keeps the active vent flap closed. With the tether released, the active vent opens to reduce airbag deployment force and reduce the possibility of an airbag-induced injury when the passenger is seated close to the deploying airbag. If the passenger front seat is not in the full forward position, the tether is not released and the active vent in the cushion remains closed during deployment.
Typically, both initiators are used during a PAB deployment event. However, it is possible for only one initiator to be used during a deployment due to an airbag system fault; therefore, it is necessary to always confirm that both initiators have been used in order to avoid the improper disposal of potentially live pyrotechnic materials. Refer to STANDARD PROCEDURE .
The ORC monitors the condition of the PAB through circuit resistance, and will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the PAB inflator, the tether release and the squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
Each side curtain airbag (also known as Side AirBag Inflatable Curtain/SABIC) is deployed individually by an electrical signal generated by the Occupant Restraint Controller (ORC) to which it is connected through the left or right SABIC line 1 and line 2 (or squib) circuits. The hybrid-type inflator assembly for each airbag contains a small canister of highly compressed inert gas. When the ORC sends the proper electrical signal to the airbag inflator, the electrical energy creates enough heat to ignite chemical pellets within the inflator.
Once ignited, these chemicals burn rapidly and produce the pressure necessary to rupture a containment disk in the inert gas canister. The inflator and inert gas canister are sealed and connected to a tubular manifold so that all of the released gas is directed into the folded airbag cushion, causing the cushion to inflate. As the cushion inflates it will drop down from the roof rail between the edge of the headliner and the side glass/body pillars to form a curtain-like cushion to protect the vehicle occupants during a side impact collision. The cushion features large chambers that inflate adjacent to the head of each front and rear seat occupant.
The front and rear tethers keep the side curtain airbag cushion taut to the side of the vehicle. In addition, the deploy brackets at the tops of the B and C-pillars guide the cushion past the upper B and C-pillar trim into the proper deployment position. Following the deployment, the cushion slowly deflates by venting the inert gas through the loose weave of the cushion fabric and the deflated cushion hangs down loosely from the roof rail.
The ORC monitors the condition of the side curtain airbags through circuit resistance, and will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the side curtain airbag inflator and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
All vehicles manufactured for sale in the United States and Canada are required to be equipped with a Lower Anchors and Tether for CHildren or LATCH child restraint anchorage system. The rear seats in this vehicle have two pairs of anchor provisions for installing a LATCH-compatible child seat. A single seat may be mounted in the center seating position, or one in each outboard seating position.
With LATCH child seats are secured by direct attachment to the vehicle structure, rather than by the seat belts. With LATCH-compatible child seats, lower (also known as ISOFIX) anchors attach to the seat structure through heavy-gauge wire loops located at the intersection between the seat cushion and the seat back surfaces.
Three upper tether anchors are integral to the rear shelf panel to secure the top tether strap of child seats equipped with this feature. These upper tether anchors work with both LATCH-compatible and other child seats equipped with a top tether strap.
The owner's information packet in the vehicle glove box contains details and suggestions on the proper use of all of the factory-installed child restraint anchors.
The clockspring is a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed instrument panel wire harness and certain electrical components mounted on or in the rotating steering wheel. On this vehicle the rotating electrical components include the Driver AirBag (DAB), the horn switch and, if the vehicle is so equipped, the odometer switch pod or the Electronic Vehicle Information Center (EVIC) switch pod, the Local Interface Network (LIN) module, the speed control switch pod and the remote radio switches. The clockspring is positioned and secured near the top of the steering column. The fixed connector receptacle on the back of the fixed Steering Column Control Module (SCCM) mounting housing connects the clockspring to the vehicle electrical system through a take out with connector from the instrument panel wire harness.
The turn signal cancel cam is integral to the rim of the clockspring rotor hub within the SCCM mounting housing so it also moves with the rotation of the steering wheel. Three short, sleeved pigtail wires on the upper surface of the clockspring rotor connect the clockspring to the DAB, while a steering wheel wire harness connected to the connector receptacle on the upper surface of the clockspring rotor completes circuits to the horn switch and, if the vehicle is so equipped, the odometer switch pod or the EVIC switch pod, the LIN module, the speed control switch pod and the remote radio switches.
Like the clockspring in a timepiece, the clockspring tape has travel limits and can be damaged by being wound too tightly during full stop-to-stop steering wheel rotation. To prevent this from occurring, the clockspring is centered when it is installed on the steering column. Centering the clockspring indexes the clockspring tape to the movable steering components so that the tape can operate within its designed travel limits.
However, if the steering shaft is disconnected from the steering gear the clockspring rotor spool can change position relative to other movable steering components. Clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black squares of the clockspring tape are not visible in the inspection window, clockspring centering has been compromised and the entire clockspring must be replaced with a new unit.
Service replacement clocksprings are shipped pre-centered and with a plastic locking tab installed. This locking tab should not be removed until the clockspring has been properly installed on the steering column. If the locking tab is removed before the clockspring is installed on a steering column, clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black squares of the clockspring tape are not visible in the inspection window, the clockspring must be replaced with a new unit.
The hard wired clockspring circuits may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and communication between stationary electronic modules and devices in the vehicle and the rotating electronic modules and devices on or in the steering wheel. The most reliable, efficient and accurate means to diagnose the electronic controls and communication related to clockspring operation requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
The Occupant Classification System (OCS) provides electronic message inputs to other electronic modules in the vehicle indicating whether the passenger front seat is occupied and the relative size classification of the seat occupant. The microcontroller within the Occupant Classification Module (OCM) contains the OCS logic and communication circuitry. The OCM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with a diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is also used for OCS diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.
The Seat Weight Sensor (SWS) (also known as the seat weight bladder) and the electronic pressure sensor integral and internal to the OCM allow the OCS logic circuits to sense the relative weight of a load applied to the passenger front seat cushion. When a load is applied to the seat cushion, silicone fluid within the bladder becomes pressurized. These changes in bladder fluid pressure are measured by the electronic pressure sensor circuitry through the OCS pressure hose. As the pressure within the bladder changes, the electronic pressure sensor input to the OCM microcontroller also changes. This electronic pressure sensor input allows the OCM to monitor the passenger front seat cushion by providing a weight-sensing reference to the relative load on the seat cushion.
Pre-programmed decision algorithms and OCS calibration allow the OCM microcontroller to determine the appropriate occupant classification based upon the seat cushion load as signaled by the pressure sensor. The OCM then sends the proper electronic occupant classification status messages over the CAN data bus to the Occupant Restraint Controller (ORC) and the ORC controls the deployment circuits for the passenger front supplemental restraints accordingly.
The OCM continuously monitors all of the OCS electrical circuits and components to determine the system readiness. If the OCM detects a monitored system fault, it sets an active and stored Diagnostic Trouble Code (DTC) and sends the appropriate electronic messages to the Occupant Restraint Controller (ORC) over the CAN data bus. Then the ORC sets a DTC and sends electronic messages to the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC) to control airbag indicator operation.
The OCM receives battery current on a fused ignition output (run-start) circuit through a fuse in the Power Distribution Center (PDC). The OCM circuitry has a path to ground at all times through a ground circuit and take out of the instrument panel wire harness, which it shares with the ORC. This take out is secured to the body sheet metal. These connections allow the OCM to be operational whenever the ignition switch status is ON or START.
The Body Control Module (BCM) stores and compares vehicle configuration data with the OCM as well as with other Electronic Control Units (ECU) in the vehicle. This process is referred to as PRogramming Of Configuration of Systems Integrated (PROCSI) (also known as PROXI). If a configuration mismatch is detected, the BCM sets a DTC. A configuration mismatch DTC will require the performance of a Restore BCM PROXI Configuration routine, or a PROXI Configuration Alignment routine using a diagnostic scan tool.
The hard wired inputs and outputs for the OCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the OCM or the electronic controls and communication between other modules and devices that provide some features of the OCS. The most reliable, efficient and accurate means to diagnose the OCM or the electronic controls and communication related to OCS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
The microcontroller within the Occupant Restraint Controller (ORC) contains the Supplemental Restraint System (SRS) logic circuits and controls all of the SRS components. The ORC uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is used for control of the airbag and seat belt indicators in the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC) and for SRS diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.
The ORC microcontroller continuously monitors all of the SRS electrical circuits to determine the system readiness. If the ORC detects a monitored system fault, it sets an active and stored Diagnostic Trouble Code (DTC) and sends electronic messages to the IC over the CAN data bus to turn ON the airbag indicator. An active fault only remains for the duration of the fault, or in some cases for the duration of the current ignition cycle, while a stored fault causes a DTC to be stored in memory by the ORC. In the case of some faults which have not recurred for a number of ignition cycles, the ORC will automatically erase the stored DTC. For other internal faults, the stored DTC is latched forever.
The ORC receives battery current through two circuits; a fused ignition output (run) circuit through a fuse in the Power Distribution Center (PDC) and a fused ignition output (run-start) circuit through a second fuse in the PDC. The ORC receives ground through a ground circuit and take out of the instrument panel wire harness that is secured by a ground screw to the body sheet metal. These connections allow the ORC to be operational whenever the ignition switch status is START or ON.
The ORC also contains an energy-storage capacitor. When the ignition switch status is START or ON, this capacitor is continually being charged with enough electrical energy to deploy the SRS components for up to one second following a battery disconnect or failure. The purpose of the capacitor is to provide backup SRS protection in case there is a loss of battery current supply to the ORC during an impact.
Various sensors within the ORC are continuously monitored by the ORC logic. These internal sensors, along with several external impact sensor inputs allow the ORC to determine both the severity of an impact and to verify the necessity for deployment of any SRS components. Two remote front impact sensors are located on the back of the right and left sides of the Front End Module (FEM) carrier inboard of the headlamps near the front of the vehicle. The electronic impact sensors are accelerometers that sense the rate of vehicle deceleration, which provides verification of the direction and severity of an impact.
The ORC also monitors inputs from the seat track position sensors, the front seat belt switches and six additional remote side impact sensors located on the left and right front door hardware module carriers, on the right and left lower B-pillars and on the right and left lower C-pillars to control deployment of the side curtain airbag units and the front and, if equipped, rear seat (also known as pelvic and thorax) airbags. The ORC also uses electronic message inputs from the Occupant Classification Module (OCM) beneath the passenger front seat cushion pan and will send electronic messages to the IC to illuminate the seat belt indicator when appropriate.
The impact sensors within the ORC are electronic accelerometer sensors that provide an additional logic input to the ORC microcontroller. These sensors are used to verify the need for a SRS component deployment by detecting impact energy of a lesser magnitude than that of the primary electronic impact sensors, and must exceed a safing threshold in order for the SRS components to deploy. A separate impact sensor within the ORC provides confirmation to the ORC microcontroller of side impact forces. The ORC uses this input to verify the need for side curtain airbags or seat airbag deployment. This separate sensor is a bi-directional unit that detects impact forces from either side of the vehicle.
This vehicle is also equipped with the Occupant Classification System (OCS). The ORC communicates with the Occupant Classification Module (OCM) over the CAN data bus. The ORC uses inputs from the OCM as an additional logic input for determining the appropriate level of airbag deployment force required for the front passenger seating position. The OCM notifies the ORC when it has detected a monitored system fault and stored a DTC in its memory for any ineffective OCS component or circuit, then the ORC sets a DTC and will send electronic messages to the IC to illuminate the airbag indicator as appropriate.
Pre-programmed decision algorithms in the ORC microcontroller determine when the deceleration rate as signaled by the impact sensors indicate an impact that is severe enough to require SRS protection. Based upon the severity of the monitored impact as well as the seat track position sensor and the passenger front seat occupant classification inputs, the ORC logic determines the level of front airbag deployment force required for each front seating position. When the programmed conditions are met, the ORC sends the proper electrical signals to deploy the dual multistage front airbags at the programmed force levels, the knee airbags, the front seat belt tensioners, either side curtain airbag and either right or left, front and rear seat airbag unit.
The Body Control Module (BCM) stores and compares vehicle configuration data with the ORC as well as with other Electronic Control Units (ECU) in the vehicle. This process is referred to as PRogramming Of Configuration of Systems Integrated (PROCSI) (also known as PROXI). If a configuration mismatch is detected, the BCM sets a DTC. A configuration mismatch DTC will require the performance of a Restore BCM PROXI Configuration routine, or a PROXI Configuration Alignment routine using a diagnostic scan tool.
The hard wired inputs and outputs for the ORC may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the ORC or the electronic controls and communication between other modules and devices that provide some features of the SRS. The most reliable, efficient and accurate means to diagnose the ORC or the electronic controls and communication related to SRS operation requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.
The inertia-activated Active Head Restraint (AHR) units are deployed automatically by the mechanism contained within each front seat back assembly. During a rear impact, inertia drives the seat occupant rearward into the seat back, loading the seat lumbar assembly. The ramp brackets at the base of the lumbar assembly translate this rearward travel into a vertical motion. The vertical motion of the lumbar assembly is then transmitted to the armature bracket.
Through the rotation of the pivot links at each side of the armature bracket, the vertical motion of the lumbar assembly is converted to a slightly forward and upward arc of the armature bracket, headrest guide tubes and headrest that is designed to reduce the space between the back of the head of the seat occupant and the head restraint pad. Closing this space catches the head of the seat occupant during a low speed rear impact collision event and is important in reducing or eliminating potentially debilitating cervical (also known as whiplash) injuries.
Unless damaged following the rear impact, the inertia-activated AHR can be reset by simply pushing the front seat headrests rearward to their normal positions.
DESCRIPTION
The seat belt retractors used in all seating positions include an inertia-type, Emergency Locking Retractor (ELR) mechanism as standard equipment. However, the ELR for all seating positions except the driver side front are mechanically switchable from an ELR to an Automatic Locking Retractor (ALR). Both front seat belt retractors also include a seat belt tensioner feature and an adaptive load limiting feature. Refer to TENSIONER, SEAT BELT, DESCRIPTION .
The ELR mechanism, the ALR mechanism, the tensioner mechanism and the adaptive load limiting feature are all integral to the seat belt and retractor unit and are concealed beneath molded plastic covers located on the sides of the retractor spool. These features cannot be adjusted or repaired and if ineffective, damaged or deployed, the entire seat belt and retractor unit must be replaced.
The standard inertia-type Emergency Locking Retractor (ELR) will allow the seat belt webbing to unwind from and wind onto the retractor spool freely unless and until a predetermined inertia load is sensed. The retractor has an internal inertia latch mechanism that will lock the retractor spool once the predetermined inertia load is sensed. Locking the retractor spool prevents the seat belt webbing from being extracted from the retractor and firmly restrains the occupant wearing the seat belt. The retractor spool is automatically unlatched once the loading of the retractor inertia mechanism and the seat belt are relieved.
The primary function of the switchable ELR to Automatic Locking Retractor (ALR) feature is to securely accommodate an infant or child booster seat in any seating position of the vehicle except the driver side front seat without the need for a self-cinching seat belt tip half latch plate unit or another supplemental device that would be required to prevent the seat belt webbing from unwinding freely from the retractor spool of an inertia-type ELR in situations where the minimum inertia locking threshold has not been achieved.
The locked mode of the ALR is engaged and the retractor is switched from operating as a standard inertia-type ELR by first buckling the combination lap and shoulder belt buckle. Then all of the shoulder belt webbing is pulled out from the retractor. Once all of the belt webbing is extracted from the retractor spool, the retractor will automatically become engaged in the pre-locked ALR mode and will make a light, audible clicking or ratchet-like sound as the shoulder belt is allowed to retract onto the spool to provide an audible confirmation that the ALR mode is engaged. Once the ALR mode is engaged, the retractor will remain locked and the belt will remain tight around whatever it is restraining.
The retractor is returned to standard ELR (inertia) mode by unbuckling the combination lap and shoulder belt buckle and allowing the belt webbing to be almost fully retracted back onto the retractor spool. The ELR mode is confirmed by the absence of the light, audible clicking or ratchet-like sound as the belt webbing retracts. This mode will allow the belt to unwind from and wind onto the retractor spool freely unless and until a predetermined inertia load threshold is sensed, or until the retractor is again switched to the ALR mode.
The Seat Track Position Sensor (STPS) is designed to provide a seat position data input to the Occupant Restraint Controller (ORC) indicating whether the driver or passenger front seat is in a full forward or a not full forward position. The ORC uses this data as an additional logic input for use in determining the appropriate force to be used when deploying the multistage Driver AirBag (DAB) or Passenger AirBag (PAB).
The STPS receives a nominal five volt supply from the ORC. The STPS communicates the seat position by modulating the voltage returned to the ORC on a sensor data circuit. The ORC also monitors the condition of the STPS circuits and will store a Diagnostic Trouble Code (DTC) for any fault that is detected. The ORC sends messages over the CAN data bus to control the illumination of the airbag indicator in the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC).
The hard wired circuits between the STPS and the ORC may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the STPS or the electronic controls and communication between other modules and devices that provide features of the Supplemental Restraint System (SRS). The most reliable, efficient and accurate means to diagnose the STPS or the electronic controls and communication related to STPS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
The driver front seat belt switch is designed to control a hard wired sense input to the Occupant Restraint Controller (ORC), while the passenger front seat belt switch controls a similar input to the Occupant Classification Module (OCM). A spring-loaded slide with a small window-like opening is integral to each buckle latch mechanism. When a seat belt tip-half is inserted and latched into the seat belt buckle, the slide is pushed downward and the window of the slide exposes the Hall-effect Integrated Circuit (IC) chip within the buckle. The field of the permanent magnet induces a current within the chip. The chip provides this induced current as an output to the ORC or the OCM. When the seat belt is unbuckled, the spring-loaded slide moves upward and shields the IC from the field of the permanent magnet, causing the output current from the seat belt switch to be reduced.
The seat belt switches receive a supply of current from the ORC or the OCM, and the ORC or OCM senses the status of the front seat belt switch through its connection to the seat wire harnesses. The ORC or the OCM provides electronic seat belt switch status messages to the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC) over the Controller Area Network (CAN) data bus. The IC uses these messages as an additional logic input for control of the seat belt indicator. The ORC and OCM monitor the condition of the seat belt switch circuits and will store a Diagnostic Trouble Code (DTC) for any fault that is detected.
The hard wired circuits between the seat belt switches and the ORC or OCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the switches or the electronic controls and communication between other modules and devices that provide some features of the seat belt reminder system. The most reliable, efficient and accurate means to diagnose the seat belt switches or the electronic controls and communication related to seat belt switch operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
The seat belt tensioners and adaptive load limiter are deployed in conjunction with the dual front airbags by signals generated by the Occupant Restraint Controller (ORC) through the individual driver or passenger retractor (or sill end), pretensioner (or anchor) or adaptive load limiter line 1 and line 2 (or squib) circuits. When the ORC sends the proper electrical signal to the tensioner and adaptive load limiter initiators, the electrical energy generates enough heat to initiate a small pyrotechnic gas generator.
In sequence, the ORC activates the retractor tensioner, followed by the anchor tensioner. The adaptive load limiter on the retractor is activated only after both the retractor and anchor buckle tensioners. The retractor tensioner gas generator drives the seat belt retractor spool causing slack to be removed from the front seat belt. The anchor tensioner gas generator pulls the buckle downward, causing the slack to be removed from the front seat belt. The ORC uses the adaptive load limiter to adjust the belt resistance based upon impact data, to reduce the force of the tightened seat belt on the chest of the front seat occupant, reducing the potential for injuries.
Removing excess slack from the front seat belts not only keeps the occupants properly positioned for an airbag deployment following a frontal impact of the vehicle, but also helps to reduce injuries that the occupants of the front seats might experience in these situations as a result of harmful contact with the steering wheel, steering column, instrument panel or windshield.
The ORC monitors the condition of the seat belt tensioners and adaptive load limiter through circuit resistance, and will illuminate the airbag indicator in the Instrument Cluster (IC) (also known as the (Instrument Panel Cluster/IPC) and store a Diagnostic Trouble Code (DTC) for any fault that is detected. Proper diagnosis of the seat belt tensioner and adaptive load limiter initiators and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.