LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2019 >> CX-9 Signature >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> On-Board Diagnostic - Airbag System (Two-Step Deployment Control System) >> DTC B1128-11/B1128-12/B1128-13/B1128-19/B1128-1A: Driver-Side Curtain Air Bag Module Circuit [SAS Control Module (Two-Step Deployment Control System)] >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

DTC B1128:11/B1128:12/B1128:13/B1128:19/B1128:1A - SAS CONTROL MODULE (TWO-STEP DEPLOYMENT CONTROL SYSTEM) DIAGNOSTIC PROCEDURE

Step Inspection Action
1 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CONNECTOR
WARNING:
Yes Replace the malfunctioning part, then go to Step 8.
No Go to the next step.
2 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CIRCUIT FOR SHORT TO GROUND
NOTE:
  • Inspect for continuity while shaking the wiring harness between the SAS control module and the driver-side curtain air bag module.
  • Is there continuity?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between SAS control module terminal and driver-side curtain air bag module terminal. If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Replace the malfunctioning part. If there is no common connector:
  • Replace the wiring harness which has a short to ground.

    Go to Step 8.

No Go to the next step.
3 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CIRCUIT FOR OPEN CIRCUIT
  • Driver-side curtain air bag module and SAS control module connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Driver-side curtain air bag module terminal A-SAS control module terminal 1C
      • Driver-side curtain air bag module terminal B-SAS control module terminal 1G
NOTE:
  • Inspect for continuity while shaking the wiring harness between the SAS control module and driver-side curtain air bag module.
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between SAS control module terminal and driver-side curtain air bag module terminal. If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Replace the malfunctioning part. If there is no common connector:
  • Replace the wiring harness which has an open circuit.

    Go to Step 8.

4 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CIRCUIT FOR SHORT TO POWER SUPPLY
  • Driver-side curtain air bag module and SAS control module connectors are disconnected.
  • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side):
    • SAS control module terminal 1C
      • SAS control module terminal 1G
NOTE:
  • Measure the voltage while shaking the wiring harness between the SAS control module and driver-side curtain air bag module.
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between SAS control module terminal and driver-side curtain air bag module terminal. If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Replace the malfunctioning part. If there is no common connector:
  • Replace the wiring harness which has a short to power supply.

    Go to Step 8.

5 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CIRCUIT FOR SHORT TO EACH OTHER
  • Driver-side curtain air bag module and SAS control module connectors are disconnected.
  • Switch the ignition off.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Driver-side curtain air bag module terminal A-SAS control module terminal 1G
      • Driver-side curtain air bag module terminal B-SAS control module terminal 1C
NOTE:
  • Inspect for continuity while shaking the wiring harness between the SAS control module and driver-side curtain air bag module.
  • Is there continuity?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between SAS control module terminal and driver-side curtain air bag module terminal. If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to each other.
  • Replace the malfunctioning part. If there is no common connector:
  • Replace the wiring harness which has a short to each other.

    Go to Step 8.

No Go to the next step.
6 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE CIRCUIT FOR SHORT TO OTHER AIR BAG MODULE CIRCUIT
  • Driver-side curtain air bag module and SAS control module connectors are disconnected.
  • Other air bag module, pre-tensioner seat belt and lap pre-tensioner seat belt connectors are disconnected.
  • Refer to the wiring diagram and inspect for continuity between the driver-side curtain air bag module terminals and other air bag module/pre-tensioner seat belt/lap pre-tensioner seat belt terminals (wiring harness-side).
NOTE:
  • Inspect for continuity while shaking the wiring harness between the SAS control module and driver-side curtain air bag module.
  • Is there continuity?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between driver-side curtain air bag module terminal and other air bag module/pre-tensioner seat belt/lap pre-tensioner seat belt terminal. If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to other air bag module, pre-tensioner seat belt or lap pre-tensioner seat belt circuit.
  • Replace the malfunctioning part. If there is no common connector:
  • Replace the wiring harness which has a short to other air bag module, pre-tensioner seat belt or lap pre-tensioner seat belt circuit.

    Go to Step 8.

No Go to the next step.
7 INSPECT DRIVER-SIDE CURTAIN AIR BAG MODULE Yes Go to the next step.
No Replace the driver-side curtain air bag module. (See CURTAIN AIR BAG MODULE REMOVAL/INSTALLATION [TWO-STEP DEPLOYMENT CONTROL SYSTEM] .)
Then go to the next step.
8 PERFORM SAS CONTROL MODULE DTC INSPECTION Yes Replace the SAS control module. (See SAS CONTROL MODULE REMOVAL/INSTALLATION [TWO-STEP DEPLOYMENT CONTROL SYSTEM] .)
No DTC troubleshooting completed.