SRS Inspection and Component Replacement

Inspection and replacement of safety restraint system (SRS) components after a collision.

This document provides instructions on what safety restraint system (SRS) components to inspect and replace following a collision.
Warning IconA warning icon, calling your attention to a possibly risky situation
Warning
After any collision, inspect the impact sensor(s) near the collision area for damage. If a sensor is damaged, replace the sensor and the hardware that secures the sensor to the body.

Parts That Must Always be Inspected Following Airbag or Seat Belt Pretensioner Deployment, and Replaced if Damaged

After any collision:

  • Inspect the harnesses and harness connectors that connect to all deployed airbags, pretensioners, and to all damaged components. Replace any damaged harnesses.
  • Inspect all seats and seat belts for visible deformation or signs of wear on the webbing. Replace any damaged components.
  • Inspect the seat belt height adjuster and webbing in the 1st row (behind the B-pillar trim) for signs of wear or deformation. Replace any damaged components.
  • Inspect all seats, seat belts, and retractors with pretensioners for visible signs of deformation or signs of wear. Replace any damaged components.
    Informational PurposesAn informational icon, calling your attention
    Note
    When inspecting the seat belt system, pay special attention to the area around the D-ring, where the seat belt webbing passes through the seat shoulder.
  • Inspect all seat belt anchor points for damage. Check for tears, bends, dents, fastener damage, or mount point damage. Assess fixing this damage before replacing any sort of seat belt component.
  • Inspect the 2nd row seat posts for full range of movement (forward and rearward, seat pitch and tracking motion). If any of the following conditions occur while inspecting, replace the seat post and seat assemblies:
    • Failure to travel the expected range
    • Unusual “metal on metal” noise during movement
    • Actuator strain
  • For all the seats that were occupied during a collision: Inspect the following components for cracks:
    • Seat pivot (remove the seat’s lower trim to inspect)
    • Angle bracket where the seat belt buckle assembly mounts to the seat assembly, as shown below (remove the seat’s back trim and seat podium cover to expose the bracket)
      Figure 1. Angle Bracket Location


  • Inspect any impact sensor(s) near the collision area for damage. If the sensor is damaged, replace the sensor, and the hardware that secures it to the vehicle. Refer to the Service Manual for more information about impact sensor replacement.
    Warning IconA warning icon, calling your attention to a possibly risky situation
    Warning
    Always replace any plugs or tape removed from the front door shells when replacing a front door pressure sensor. Additional holes in the door create more escape paths for air, which decreases the sensor's ability to detect a side impact, and can negatively affect airbag deployment.
  • Inspect any undeployed knee airbag:
    • If the knee airbag cover is damaged, or if there are 3 or more consecutive broken bridges (as shown below) or 5 or more broken bridges total, replace the complete knee airbag assembly.


    • If there are visible signs of damage to the knee air bag cushion (such as scuffs, rips or holes) replace it.
    • Inspect the knee airbag module for visual damage (such as bent hooks or scuffing), and replace it if damaged.
  • Adjust the steering column so that the column shaft (shown in yellow below) is fully retracted inside of the housing. Measure the C-channels (shown in red) on the side of the steering column. If the left C-channel is recessed more than 2.1 mm into the housing, or the right C-channel protrudes less than 19.5 mm from the housing, replace the steering column.


  • Inspect Pedestrian Protection components on the vehicle if it is equipped with Pedestrian Protection (see Pedestrian Protection Components for more information), and replace any damaged components.
  • Use Toolbox to test the supplementary restraint system for proper operation.
    1. Connect a laptop to the diagnostic port of the vehicle, and then use Toolbox 3 to locally connect to the vehicle. See Toolbox 3 (Connect and Disconnect).
    2. Unlock the vehicle gateway for diagnostic communication. See Gateway Unlock.
    3. In Toolbox 3, click Dashboards > Service Tools > DTCs, and then select SDM or RCM depending on the vehicle Restraint Control Type.
    4. Click Read DTCs to display the DTCs.
    5. Power cycle the vehicle.
    6. Click Clear DTCs to clear the DTCs.
    7. Determine the RCM type of the vehicle under cfg_restraint_controls. See Gateway Configuration (Display and Change). If the config shows "DelphiSDM", revert to Toolbox 2 to test the restraint system. If the config shows "BoschRCM", perform the next steps:
    8. Turn on the drive rails.
    9. In Toolbox 3, click the Actiions tab, type "RCM" into the search field, select PROC_RCM_X_SERVICE-TASKS, click Run, and allow the routine to complete.
    10. Cycle the drive rails.

Parts That Must be Replaced Following Airbag or Seat Belt Pretensioner Deployment

After a collision when a seat belt pretensioner deployed, replace the following items and all accompanying fasteners:
  • The RCM (Restraint Control Module).
  • Any seat belt that has a deployed pretensioner, and the accompanying seat belt buckle.
  • Any seat belts and buckles that were in use during the collision.
  • If any airbag has deployed, replace the pyrotechnic battery disconnect fuse.
    Informational PurposesAn informational icon, calling your attention
    Note
    If a seat belt pretensioner deployed, but no airbag deployed, replace the pyrotechnic battery disconnect fuse only if blown.
    Informational PurposesAn informational icon, calling your attention
    Note
    Do not replace the pyrotechnic battery disconnect fuse unless it has been positively confirmed that the vehicle will be repaired.
In addition to the parts replaced after a seat belt pretensioner deployed, replace the following items and all accompanying fasteners after a collision when an airbag deployed:
  • Replace any deployed airbag and all accompanying fasteners.
  • If the driver’s front airbag has deployed, replace the steering wheel assembly.
  • If a side (seat mounted) airbag has deployed, replace the 1st row seat assembly that contains the deployed airbag.

Pedestrian Protection Components

Model X vehicles are equipped with Pedestrian Protection components such as a pressure sensing tube, and hood actuators.

Figure 2. Pedestrian Protection Pressure Sensing Tube


Figure 3. Pedestrian Protection Hood Actuator (LH)


Figure 4. Pedestrian Protection Hood Actuator (RH)


To determine if a vehicle is equipped with Pedestrian Protection components, open the hood and look for Pedestrian Protection hood actuators, as shown above.

If the vehicle is equipped with Pedestrian Protection components, after a frontal collision:

  • Replace the Pedestrian Protection hood actuators if they deployed.
  • Inspect the Pedestrian Protection pressure sensor tube and connector for signs of damage, such as tears in the tube and cracks in the connector. Replace the pressure sensor assembly if any part has been damaged.

Part Information

Current airbag component part information can be obtained through the VIN decode feature of the Parts Manual.

For Further Assistance

For further assistance, contact your local Collision Repair Support team as described in .