Restraints

General Information

General

The Supplemental Restraint System (SRS) is designed to supplement the seat belt to help reduce the risk or severity of injury to the driver and front passenger by activating and deploying the driver, passenger, side airbags and seat belt pretensioners in certain frontal or side collisions.

The SRS (Supplemental Restraint System) consists of: the driver's side airbag module located in the center of the steering wheel, which contains the folded airbag and inflator unit; the passenger's side airbag module located in the instrument panel, which contains the folded airbag assembly with inflator unit; side airbag modules located in the front seats, which contain the folded airbag and inflator unit; curtain airbag modules located inside the headliner, which contain folded airbags and inflator units. The SRSCM crash detection function is performed by an electronic accelerometer that continuously measures vehicle acceleration and sends the corresponding signal through amplification and filter circuits to the microprocessor.

SRSCM (SRS Control Module)

The SRSCM detects a frontal collision with the frontal impact sensor and a side collision with the side impact sensor to determine airbag module deployment.

1. 1

   DC/DC Converter: The DC/DC converter in the power supply includes a step-up/step-down transformer converter and provides the ignition voltage for the 2 front airbag circuits and the internal operating voltage of the SRSCM. If the internal operating voltage falls below the critical value, it will reset.

2. 2

   Backup Power Supply: The SRSCM has a separate backup power supply that provides instant deployment energy in low voltage conditions or when power supply is interrupted due to a frontal collision.

3. 3

   Self-Diagnosis: The SRSCM continuously monitors the current operating status of the SRS and detects system malfunctions while the vehicle power is on. System malfunctions can be checked using trouble codes with the KDS/GDS.

4. 4

   Airbag Warning Lamp Illuminated: When a malfunction is detected, the module sends a signal to the SRSCM warning lamp located on the instrument panel. The MIL will alert the driver to an SRS malfunction. When the ignition is turned on, the SRS lamp illuminates for approximately six seconds.

5. 5

   Trouble Code Recording: When a malfunction occurs in the SRSCM system, the DTC corresponding to the malfunction is stored. DTCs can only be erased using the KDS/GDS. However, if an internal malfunction code is recorded or a failure is registered, the trouble code(s) cannot be erased.

6. 6

   Self-Diagnosis Connector: The data stored in the SRSCM memory is output to the KDS/GDS or other external output devices through the connector located below the driver's side airbag.

7. 7

   After the airbag has deployed, the SRSCM must not be reused and must be replaced.

8. 8

   The SRSCM determines whether the passenger is wearing the seat belt based on the signal from the built-in switch in the seat belt buckle, and deploys the front passenger airbag at every emergency deceleration.

9. 9

   Side airbag deployment is determined by the SRSCM detecting the satellite impact sensor signal during a side collision, regardless of seat belt status.

10. 10

    The SRSCM detects vehicle rollover using the roll-over sensor. The SAB, CAB, and BPT may deploy if the technician moves the SRSCM while the IGN is in the ON state. For this reason, disconnect the negative battery cable during SRSCM repair procedures.

11. 11

    After the repair procedure, check that the SRSCM operates normally.

Specifications

Specification

Tightening torque

Special Service Tools

Special Service Tools

Tool Name/Number	Illustration	Description
Deployment Tool 0957A-34100A		Used to deploy the airbag
Deployment Adapter 0K57A-3U100A		Used with the deployment tool (0957A-34100A) when deploying DAB, PAB, CAB, BPT, EFD
Deployment Adapter 0957A-2W100		Used with the deployment tool (0957A-34100A) when deploying SAB
Dummy Unit 0957A-38200		Airbag Wiring Harness Resistance Check Simulator
Dummy Adapter 0957A-2W200		Used with the dummy (0957A-38200) when checking SAB resistance
Dummy Adapter 0957A-2G000		Used with the dummy (0957A-38200) when checking the resistance of DAB, PAB, CAB, BPT, EFD

DAB: Driver Airbag

PAB: Passenger Airbag

SAB: Side Airbag

CAB: Curtain Airbag

BPT: Seat Belt Pretensioner

General Safety Information and Precautions

Precautions

General Precautions

Carefully read the following precautions before servicing the airbag system.

Follow the instructions in this manual, otherwise the airbags may deploy unintentionally and cause damage or injury.

• Except when inspecting the electrical system, always turn the ignition OFF and disconnect the negative battery cable, then wait at least three minutes before starting work.

• Use replacement parts manufactured to the same standards as genuine parts and of good quality.

  Do not install used SRS parts from another vehicle. Use only new parts when repairing the SRS.

• Carefully inspect any SRS component before installation. Do not install any part that shows signs of being dropped or mishandled, such as dents, cracks or deformation.

  

• Before removing any SRSCM component (including disconnecting connectors), always disconnect the SRSCM connector.

Airbag Control and Storage

Do not disassemble the airbags; they have no serviceable parts. Once an airbag has deployed, it cannot be repaired or reused.

For temporary storage of the airbag during service, observe the following precautions.

• Store the removed airbag with the pad facing up.

• Do not allow oil, grease, cleaning agents, or water to contact the airbag module to prevent damage.

  

• Store the removed airbag on a solid, flat surface away from heat sources (above 85 C/185 F).

• Never perform electrical tests on airbags, such as measuring resistance.

• Do not stand in front of the airbag module during removal, inspection, or replacement.

• Refer to the disposal procedures for a deployed or damaged airbag.

• Be careful not to strike the SRS unit or side impact sensors or frontal impact sensors. Whenever the ignition switch is in the ON position, wait at least three minutes after turning the ignition off before starting work.

• During installation or replacement, be careful not to strike the area around the SRS unit and the side impact sensors and front impact sensors with a wrench, hammer, etc. The airbags may deploy unintentionally and cause damage or injury.

• Replace the front airbag module, SRSCM, FIS if the front airbag has deployed. Replace the airbag wiring if damaged. Replace the side airbag module, curtain airbag module, SRSCM, SIS if the side airbag has deployed. Replace the airbag wiring if the airbag wiring is damaged.

• After a collision in which the airbags or side airbags did not deploy, inspect the SRS unit and side impact sensors for damage or deformation. If damaged, replace the SRS unit, front impact sensor, and/or side impact sensors.

• Do not disassemble the SRS unit, front impact sensor, or side impact sensors.

• Turn the ignition off, disconnect the negative battery cable and wait at least three minutes before starting installation or replacement of the SRS unit.

• Make sure the SRS unit, front impact sensor, and side impact sensors are securely fastened with the mounting bolts.

• Do not spill water or oil on the SRS unit, front impact sensor, or side impact sensors, and protect them from dust.

• Store the SRS unit, frontal impact sensor and side impact sensors in a cool (15 ~ 25 C/59 ~ 77 F) and dry (relative humidity 30 ~ 80 %, non-condensing) area.

Connection Precautions

SRS wiring can be identified by its special yellow outer covering. Follow the instructions described in this section.

• Never attempt to modify, splice, or repair SRS wiring. If there is an open circuit or damage to the SRS wiring, replace the harness.

  

• Make sure the harness wires are routed so that they are not pinched or interfere with other parts.

  

• Make sure all SRS ground points are clean and the grounds are securely fastened for optimal metal-to-metal contact. Poor grounding can cause intermittent problems that are difficult to diagnose.

Electrical Precautions and Inspection

• When using electrical test equipment, insert the tester probe from the wire side of the connector.

  Do not insert the tester probe into the terminal side of the connector, and do not touch the connector terminals.

  

• Use a U-shaped probe. Do not force the probe into the connector.

• Use the specified service connectors for troubleshooting.

  Using improper tools may cause an inspection error due to poor metal-to-metal contact.

Spring-Loaded Lock Connector

Some SRS connectors have a spring lock.

Airbag Connector

Disconnection

To unlock the lock, pull the spring-loaded bushing (A) and slider (B) while holding the opposite half of the connector.

Separate the connector halves. Be sure to pull on the sleeve, not on the connector half.

Connection

While holding both halves of the connector, press until the projection (C) on the coupling side clicks into place to lock the connector.

Description and Operation

Warning Lamp Activation

Warning Lamp Behavior After Ignition ON

As soon as operating voltage is supplied to the SRSCM ignition input, the SRSCM activates the warning lamp for LED lamp check.

The lamp should illuminate for 6 seconds during the initialization phase, then turn off.

To warn the driver, the warning lamp must illuminate for 6 seconds and turn off for 1 second, then remain illuminated continuously after operating voltage is supplied if any active fault is present.

1. 1

   The active fault counter or historical fault counter is greater than or equal to 10.

   

2. 2

   The normal or historical fault counter is less than 10.

   

3. 3

   When the ignition is turned on in variant coding (EOL) mode, the airbag warning lamp illuminates and flashes at 1-second intervals until coding is completed.

   If variant coding is completed normally, the airbag warning lamp illuminates for 6 seconds and then turns off. Otherwise, the airbag warning lamp flashes continuously at 1-second intervals.

   1. If variant coding is completed normally.

      

   2. If variant coding is not completed.

      

   If there is an active fault in the airbag system or an internal SRSCM malfunction, variant coding (EOL) cannot be completed. In this case, repeat the variant coding (EOL) procedure after troubleshooting with the KDS/GDS.

Independent SRSCM Warning Lamp Activation

There are certain failure conditions in which the SRSCM cannot function and therefore cannot control the operation of the warning lamp. In these cases, the warning lamp is activated directly by the corresponding circuit, which operates independently of the SRSCM. These cases are:

1. 1

   Loss of SRSCM battery power: warning lamp remains on continuously.

2. 2

   Loss of internal operating voltage: warning lamp remains on continuously.

3. 3

   Loss of microprocessor operation: warning lamp remains on continuously.

4. 4

   SRSCM not connected: warning lamp remains on continuously.

Warning Lamp Activation

The indicator lamp shows whether the passenger airbag (PAB) is on or off depending on passenger seat occupancy. If the passenger seat is empty or occupied by a child (or child seat), the passenger airbag is deactivated and the indicator lamp illuminates to inform the driver that the PAB is off. Once voltage is supplied to the SRSCM ignition input, the SRSCM illuminates the indicator lamp for verification. The ODS (Occupant Detection System) sends an indeterminate status to the SRSCM as the default setting for passenger airbag deployment during the verification period.

After the ignition is turned on, the warning lamp illuminates for 4 seconds and turns off for 3 seconds during the initialization phase, and then remains on until a valid activation message is received from the ODS system.

Repair Procedures

Component Replacement After Deployment

If the front airbags deployed after a collision, replace the following parts.

• SRSCM

• Deployed airbag(s)

• Seat belt pretensioner(s)

• Front impact sensors

• Inspect the clock spring for heat damage.

  If any damage is found, replace the clock spring.

If the side/curtain airbags have deployed after a collision, replace the following items.

• SRSCM

• Deployed airbag(s)

• Side impact sensor(s) on the deployed side(s)

After completing all repairs to the vehicle, make sure the SRS airbag system is functioning properly.

• Turn the ignition ON. The SRS indicator should illuminate for approximately six seconds and then turn off.

Components and Component Location

Component Location