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 Lost Communication with XXX 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 1 voltage to the SDM is more than 9 V.
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This step determines if ignition 1 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 1 voltage circuit, and also for a high resistance in the power feed circuit to the AIR BAG Fuse.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the A Diagnostic System Check-SIR? | -- | ||
2 | Did you perform the A Diagnostic System Check-Instrument Cluster? | -- | Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console | |
Does the AIR BAG warning lamp flash seven times? | -- | |||
4 | Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console. Did you complete the replacement? | -- | -- | |
Does the scan tool indicate that DTC U1088 is current? | -- | Go To DTC U1000 and DTC U1255 Class 2 Communication Malfunction 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 Battery Inspection/Test in Engine Electrical | ||
Does the connector exhibit any signs of corrosion or damage? | -- | |||
10 | Replace the 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 | |||
12 | Locate and repair an open or high resistance in the ignition 1 circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
13 | Locate and repair a high resistance in the power feed circuit to the AIR BAG fuse. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
14 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | -- | |
15 |
Have all SIR and Instrument Cluster components been properly connected and mounted? | -- | -- |
