Circuit Description
The AIR BAG warning lamp is controlled by the inflatable restraint sensing and diagnostic module (SDM) via Class 2 serial data. When the ignition switch is first turned to the RUN position, the SDM performs tests to diagnose critical malfunctions within itself. The SDM then commands the AIR BAG warning lamp OFF after it has flashed seven times.
Diagnostic Aids
| • | If Ignition 1 voltage is outside of the normal operating voltage range (9 -16 volts), the AIR BAG warning lamp will come ON solid with no DTC's set. |
| • | The loss of serial data communication between the inflatable restraint sensing and diagnostic module (SDM) and the instrument panel cluster (IPC), will cause the AIR BAG warning lamp to come ON solid. Refer to DTC U1001-U1254 Loss of XXX Communications in Data Link Communications. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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This step checks to see if the AIR BAG warning lamp flashes seven times when the ignition switch is first turned to the RUN position.
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This step checks to see if DTC U1088 is present in the instrument panel cluster (IPC).
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This step checks to see if the AIR BAG warning lamp is being commanded ON.
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This step checks to see if ignition positive voltage to the SDM is more than 9 V.
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This step determines if ignition positive voltage to the SDM is more than 16 V or if there is a malfunctioning SDM.
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This step inspects the SDM wiring harness connector for corrosion or damage.
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Tests for an open or high resistance in the ignition positive voltage circuit between the SDM and the AIR BAG Fuse.
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Tests for an open or high resistance in the ignition positive voltage circuit to the AIR BAG Fuse.
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Tests for an open or high resistance in the SDM ground circuit or if there is a malfunctioning SDM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the SIR Diagnostic System Check? | -- | ||
2 | Did you perform the Instrument Cluster Diagnostic System Check? | -- | Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console | |
Does the AIR BAG warning lamp flash seven times? | -- | |||
Does the scan tool indicate that DTC U1088 is current? | -- | Go To DTC U1001-U1254 Loss of XXX Communications in Data Link Communications | ||
Use the scan tool to request the instrument cluster DTC display. Does the AIR BAG warning lamp command ON? | -- | |||
Does the ignition voltage displayed measure more than the specified value? | 9 V | |||
Does the ignition voltage displayed measure more than the specified value? | 16 V | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | ||
Does the connector exhibit any signs of corrosion or damage? | -- | |||
9 | Repair or replace the inflatable restraint sensing and diagnostic module (SDM) wiring harness connector. Refer to Connector Repairs in Wiring Systems. Did you complete the replacement? | -- | -- | |
Does the resistance measure within the specified value? | 0-2 ohms | |||
11 | Locate and repair an open or high resistance in the ignition positive circuit between the AIR BAG Fuse and the SDM wiring harness connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
Does the voltage measure near the specified value? | 12 V | |||
13 | Locate and repair an open or high resistance in the power feed circuit to the AIR BAG Fuse.Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
UsingJ 39200 DMM measure the resistance of the inflatable restraint sensing and diagnostic module (SDM) ground circuit between the SDM wiring harness connector and a known good ground. Refer to Circuit Testing in Wiring Systems. Does the resistance measure less than the specified value? | 2 ohms | |||
15 | Locate and repair an open or high resistance in the inflatable restraint sensing and diagnostic module (SDM) ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
16 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | -- | |
17 | Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console. Did you complete the replacement? | -- | -- | |
18 |
Have all SIR and Instrument Cluster components been properly connected and mounted? | -- | -- |
