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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System >> Diagnostic Tests >> Air Bag Warning Light Circuit Malfunction >> Diagnostic Procedure

Diagnostic Procedure

  1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to SIR DIAGNOSTIC SYSTEM CHECK .
  2. Check Instrument Panel Cluster (IPC) for correct operation. If IPC is working correctly, go to next step. If IPC is not working correctly, diagnose and repair IPC. Go to step  16.
  3. Turn ignition off. Observe AIR BAG warning light when turning ignition on. If AIR BAG warning light flashes 7 times, go to next step. If AIR BAG warning light does not flash 7 times, go to step  13.
  4. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel. Turn ignition on. Using scan tool, establish communication with IPC. Request IPC DTC display. If DTC U1088 is not retrieved, go to next step. If DTC U1088 is retrieved, diagnose and repair data link communication circuits.
  5. Using scan tool, turn AIR BAG warning light on. If AIR BAG warning light comes on, go to next step. If AIR BAG warning light does not come on, go to step  13.
  6. Using scan tool, request SIR data list. If ignition voltage is more than 9 volts, go to next step. If ignition voltage is 9 volts or less, go to step  8.
  7. If ignition voltage is more than 16 volts, inspect vehicle electrical system. If ignition voltage is 16 volts or less, go to step  15.
  8. Turn ignition off. Disconnect SDM harness connector. If SDM harness connector shows signs of corrosion, poor connections or damage, go to step  14. If SDM harness connector is okay, go to next step.
    NOTE: Use Digital Multimeter (J-39200) and Connector Test Adapter Kit (J-35616-A) or Flat Wire Probe Adapter Kit (J-42675) when performing electrical tests.
  9. Turn ignition off. Measure resistance in circuit 1139 between fuse block and SDM harness connector terminal A1. See Figure. If resistance is more than 2 ohms, go to next step. If resistance is 2 ohms or less, go to step  11.
  10. Repair open or high resistance in circuit 1139. See WIRE REPAIR . Go to step  16.
  11. Turn ignition on. Measure voltage between battery side of SIR fuse terminal and ground. If voltage is near 12 volts, go to next step. If voltage is not near 12 volts, locate and repair source of voltage loss. Go to step  16.
  12. Turn ignition off. Measure resistance between SDM harness connector terminal A18 and ground. If resistance is less than 2 ohms, go to step  15. If resistance is 2 ohms or more, repair high resistance in circuit 1851. See WIRE REPAIR . Go to step  16.
  13. Replace IPC. See INSTRUMENT PANEL CLUSTER (IPC)  under REMOVAL & INSTALLATION. Go to step  16.
  14. Replace SDM harness connector. See WIRE REPAIR . Go to step  16.
  15. Replace SDM. See SENSING & DIAGNOSTIC MODULE (SDM)  under REMOVAL & INSTALLATION. Go to next step.
  16. Reconnect all SIR system components. Ensure that all components are properly mounted. Go to SIR DIAGNOSTIC SYSTEM CHECK .
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