Air Bag and Safety Belt Pretensioner SRS

AIR BAG AND SAFETY BELT PRETENSIONER SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

The air bag supplemental restraint system (SRS) is designed to provide increased collision protection for front seat occupants in addition to that provided by the three-point safety belt system. The SRS will also provide increased collision protection for the rear occupants when equipped with optional side air curtains. Safety belt use is necessary to obtain the best occupant protection and to receive the full advantage of the SRS.

This vehicle line contains dual-stage deployment (advanced restraint system) driver and front passenger air bag modules. These vehicles are also equipped with seat side air bag modules and optional side air curtain modules.

Vehicles equipped with side air curtain modules are also equipped with seat side thorax air bag modules. Vehicles that are not equipped with side air curtain modules are equipped with seat side air bag modules. Seat side air bag modules and seat side thorax air bag modules deploy from the outboard front seat backrest upon a side impact. Side air curtain modules deploy from the headliner, protecting the first and second row outboard occupants during a side impact.

Driver Air Bag Module

NOTE: References to the driver air bag module must not be confused with the driver seat side air bag components of the supplemental restraint system (SRS).

The driver air bag module:
- is steering wheel mounted.
- will deploy upon receiving a flow of current from the restraints control module (RCM).
- has no subassemblies.

Clockspring
The clockspring:
- is mounted on the steering column, behind the steering wheel.
- provides a continuous electrical path from the driver air bag module to the restraints control module (RCM).

Seat Side Air Bag Modules and Seat Side Thorax Air Bag Modules

CAUTION: When installing a seat side air bag module or a seat side thorax air bag module always make sure the correct module is being installed. Seat side air bag modules and seat side thorax air bag modules are not interchangeable. The electrical connectors are different between the modules. DO NOT damage or alter the electrical connectors.

NOTE: When installing a new side air bag module or a new side thorax air bag module after deployment, refer to Seats.

This vehicle is equipped with a seat side air bag module or a seat side thorax air bag module. The modules are not interchangeable. The electrical connectors are keyed differently between the modules. DO NOT damage or alter the electrical connectors in any way.

A specific seat side air bag wiring harness is used for a seat side air bag module, with a unique, specific seat side air bag wiring harness used for a seat side thorax air bag module. The electrical connectors to the module and to the body main wiring harness are keyed differently on a seat side air bag wiring harness than those used on a seat side thorax air bag wiring harness. The seat side air bag wiring harness and the seat side thorax air bag wiring harness are not interchangeable.

Seat Side Air Bag Modules
The seat side air bag module is a carryover component used on prior model year vehicles. A seat side air bag module provides combined protection of the head area and thorax area (between the neck and abdomen) of the body. A seat side air bag module is physically larger than a seat side thorax air bag module. Although a seat side air bag module and a seat side thorax air bag module are similarly mounted to the front seat backrests, the modules are not interchangeable. Vehicles equipped with a seat side air bag module will not be equipped with side air curtain modules.

The seat side air bag module:
- will deploy upon receiving a flow of current from the restraints control module (RCM) initiated by the side impact sensor and internal RCM circuitry.
- is installed as an assembly.
- is mounted in the front seat backrests.
- is not interchangeable with a seat side thorax air bag module.

Seat Side Thorax Air Bag Modules
The seat side thorax air bag module is a new component being introduced on this vehicle. A seat side thorax air bag module provides protection of the thorax area (between the neck and abdomen) of the body, working in conjunction with the head protection provided by a side air curtain module. A seat side thorax air bag module is physically smaller than a seat side air bag module. Although a seat side thorax air bag module and a seat side air bag module are similarly mounted to the front seat backrests, the modules are not interchangeable. Vehicles equipped with seat side thorax air bag modules will also be equipped with side air curtain modules.

The seat side thorax air bag module:
- will deploy upon receiving a flow of current from the restraints control module (RCM) initiated by the side impact sensors and internal RCM circuitry.
- is installed as an assembly.
- is mounted in the front seat backrests.
- is used in conjunction with a side air curtain.
- is not interchangeable with a seat side air bag module.

Side Air Curtain Module

WARNING:
- The side air curtain must be installed in the vehicle using new torque-prevailing type U-nuts, part number W520822. Use of this U-nut is mandatory so as to reduce the risk of loss of fastener effectiveness. Failure to follow these instructions can result in personal injury in the event of a side air curtain deployment.
- Anytime the side air curtain has deployed, the headliner, and all A, B, and C pillar upper trim panels and attaching hardware must be replaced along with any other damaged components and hardware. Failure to do so can result in personal injury in the event of a side air curtain deployment.

NOTE: If the headliner has the word "AIRBAG" embossed on it near each B-pillar, the vehicle is equipped with side air curtain modules.

The side air curtain module:
- will deploy upon receiving a flow of current from the restraints control module (RCM) initiated by the side impact sensors and internal RCM circuitry.
- is installed as an assembly.
- is mounted above the headliner.
- attaches from the A-pillar frame to the C-pillar frame.
- cannot be interchanged from side to side.

Side Air Curtain Bridge Resistor

NOTE: Do not deactivate the side air curtain module circuit by removing the bridge resistor from the electrical connector.

If the side air curtain bridge resistor is removed, an open circuit fault will be generated by the restraints control module (RCM).

If a restraint system diagnostic tool is installed at the side air curtain electrical connector, a low-resistance fault will be generated.

The side air curtain bridge resistors:
- are equipped on vehicles without side air curtain modules.
- must not be removed in the deactivation procedure.
- are located on the driver side of the vehicle on the wiring harness.

Occupant Classification Sensor

CAUTION:
- If installing only the front passenger seat cushion trim cover, the seat occupant classification sensor (OCS) must be rezeroed.
- The following precautions must be taken before rezeroing of the OCS system.
- Make sure the OCS system components are connected and no faults are present.
- Make sure the vehicle has not been exposed to temperatures below 6°C (42°F) or above 36°C (97°F) within four hours prior to the rezeroing process. If the vehicle has been exposed to temperatures outside the temperature limits (6-36°C), the vehicle must be exposed to and kept at a temperature within the limits for minimum of four hours.
- Make sure nothing is present on the passenger seat before rezeroing and nothing is placed on the seat during the rezeroing process.
- Make sure a minimum five second time period has passed after cycling the ignition switch ON before the rezeroing process.

NOTE:
- It is necessary to rezero the OCS system when a front passenger seat cushion is disassembled, a new trim cover installed, or an OCS service kit is installed. A scan tool is used to trigger the active command to carry out rezeroing of the OCS system.
- When using a New Generation STAR (NGS) Tester, the OCS system rezero function is on the Ford Service Function (red) card. To rezero the OCS system:
- select "SERVICE BAY FUNCTIONS"
- select "RCM"
- select "SYSTEM RESET"
- select the vehicle from the menu
- view the on-screen information then press "TRIGGER"

The NGS screen will then display "OCS RESET: REZERO". Press "DONE" (button 8) to rezero the OCS system. The NGS will return to the vehicle menu once rezeroing of the OCS system is complete.

NOTE: To rezero the OCS system using the Worldwide Diagnostic System (WDS):
- select the "Toolbox" icon
- select "Body" from the menu
- select "Restraints" from the menu
- select "Seat Weight Sensor ReZero"

After selecting "Seat Weight Sensor ReZero", follow the on-screen prompts to carry out rezeroing of the OCS system.

NOTE: If the first attempt to rezero the OCS system is unsuccessful, a second attempt must be made.

The seat occupant classification sensor system is found only on the front passenger seat. The front passenger seat occupant classification sensor (OCS) system is comprised of a silicone gel-filled bladder mounted in the seat cushion, a pressure sensor that is mounted to the seat frame and an electronic control unit which is also mounted to the seat frame. Pressure is applied to the OCS bladder when weight of any occupant or object in the front passenger seat is present. The pressure is then transferred through a tube, is sensed by the OCS pressure sensor, then electronically communicated to the OCS electronic control unit. Based on programed limits, the OCS electronic control unit will inform the restraints control module (RCM), via a High Speed Controller Area Network (CAN), of the necessary information. The RCM uses this information in determining if the passenger air bag module or passenger seat side air bag module is to be deployed in the event of a deployable collision. The OCS system components (seat cushion foam pad, bladder with pressure sensor and electronic control unit) are calibrated to each other and are serviced as an assembly. OCS system components are not to be installed separately. If installing a new OCS system, OCS system component or seat cushion foam pad, a new OCS system service kit (seat cushion foam pad, bladder with pressure sensor and electronic control unit) must be installed as an assembly.

Passenger Air Bag Module

NOTE: References to the passenger air bag module must not be confused with the passenger seat side air bag components of the supplemental restraint system (SRS).

The passenger air bag module:
- will deploy upon receiving a flow of current from the restraints control module (RCM) initiated by the front impact severity sensor and internal RCM circuitry.
- is installed as an assembly.
- is mounted in the passenger side of the instrument panel.

Safety Belt Pretensioners
As part of the supplemental restraint system (SRS), the safety belt retractors are equipped with pretensioners. The safety belt retractor pretensioners rotate the safety belt retractors to remove excess slack from the safety belt webbing. The pretensioners are activated by the restraints control module (RCM) when the module detects a frontal impact event exceeding a programmed limit.

Safety Belt Switch
As part of the supplemental restraint system (SRS), the driver and passenger safety belt buckles are equipped with a belt buckle connect switch. The safety belt switches indicate to the restraints control module (RCM) whether the safety belt buckles are connected or disconnected.

The safety belt switches are also used for the driver safety belt warning system and the driver and passenger belt minder.

Restraints Control Module (RCM)

WARNING: The restraints control module (RCM) orientation is critical for correct air bag supplemental restraint system (SRS) operation. If a vehicle equipped with an SRS system has been involved in a collision in which the center tunnel area has been damaged, inspect the mounting and bracket for deformation. If damaged, the RCM must be replaced whether or not the air bags have deployed. In addition, make sure the area of the RCM mounting is restored to its original condition.

NOTE: When installing a new restraints control module (RCM), always make sure the correct RCM is being installed. If an incorrect RCM is installed, erroneous DTCs will result.

The restraints control module (RCM) is mounted on the center tunnel under the instrument panel. The RCM carries out the following functions:
- supplies current flow to the inflators to deploy the air bags in the event of a deployable crash.
- activates the safety belt retractor pretensioners to remove slack from the safety belt.
- monitors the air bag supplemental restraint system (SRS) for faults.
- illuminates the air bag indicator if a fault is detected.
- flashes the air bag indicator to indicate the lamp fault code (LFC) detected.
- communicates through the data link connector (DLC) the current or historical diagnostic trouble codes (DTCs).
- signals the instrument cluster module to activate a chime if the air bag indicator is not available and another SRS fault exists.
- contains an internal safing sensor which is not serviced separately.
- records deployment event data.

The RCM monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the RUN position, the RCM will illuminate the air bag indicator located in the instrument cluster.

When the ignition is cycled (turned off and then on), the air bag indicator will remain lit for six seconds and then go out. If an SRS fault exists, the air bag indicator will then flash the two-digit LFC. The air bag indicator will flash the LFC three times, then it will remain illuminated for the rest of the key cycle. The RCM will also communicate the current and historical DTCs through the (DLC), using a scan tool. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the instrument cluster module to activate an audible chime. The chime is a series of five sets of five tone bursts. If the chime is heard, the SRS and the air bag indicator require repair.

LFCs are prioritized. If two or more faults occur at the same time, the fault having the highest priority will be displayed first. After that fault has been corrected, the next highest priority fault will be displayed.

The RCM includes a backup power supply. This feature provides sufficient current to deploy the front air bags and safety belt pretensioners in the event that the ignition circuit is damaged or lost in a collision before the RCM determines that air bag deployment is required. The backup power supply will deplete its stored energy approximately one minute after the battery ground cable is disconnected.

Electrical System
The electrical system that supports the air bag supplemental restraint system (SRS):
- receives power from the battery through the ignition circuit.
- provides the electrical path from the restraints control module (RCM) to the SRS components.
- provides the electrical ground path for the air bag indicator.
- provides the electrical path from the RCM to the data link connector (DLC).
- provides the electrical ground path from the instrument cluster to the RCM.

Impact Sensors

WARNING: The restraints control module (RCM) orientation is critical for correct system operation. If a vehicle equipped with an air bag supplemental restraint system (SRS) has been involved in a collision in which the vehicle center tunnel area has been damaged, inspect the RCM mounting and bracket for deformation. If damaged, the RCM must be replaced whether or not the air bags have deployed. in addition, make sure the area of the RCM mounting is restored to its original condition.

The RCM incorporates integral sensors that are not separately serviceable. All vehicles will have a front impact severity sensor located behind the front radiator grille. In addition, there are two side impact sensors located on the driver and passenger side near the B-pillars. In addition to the B-pillar side impact sensors there are two additional side impact sensors mounted near the driver and passenger C-pillars when the vehicle is equipped with driver and passenger side air curtain modules. The RCM is mounted on the center tunnel under the instrument panel. Mounting orientation is critical for correct operation of all impact sensors.