Circuit Description
When the ignition is turned ON, the instrument panel cluster (IPC) flashes the AIR BAG indicator seven times. The inflatable restraint sensing and diagnostic module (SDM) performs diagnostic tests on the SIR system and then commands the IPC to turn the AIR BAG indicator OFF if no SIR malfunction exists. The AIR BAG indicator is controlled by the SDM via Class 2 serial data. If the ignition 1 voltage is outside of the normal operating voltage range 9-16 volts, the SDM will command the IPC to turn the AIR BAG indicator ON with no diagnostic trouble codes (DTCs) present.
Diagnostic Aids
The IPC will turn the AIR BAG indicator ON if there is a loss of serial data communication between the IPC and the SDM. For more detailed information concerning the Class 2 data lines, refer to Data Link Communications Description and Operation in Data Link Communications.
The following are possible causes of the malfunction:
| • | Ignition 1 voltage out of range |
| • | An internal IPC malfunction |
| • | An internal SDM malfunction |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests to see if the scan tool can communicate with the IPC.
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Tests to see if the ignition 1 voltage is more than 9 V.
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Tests to see if the ignition 1 voltage is more than 16 V.
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Tests to see if the SDM connector is damaged or corroded.
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Tests to see if there is an open or high resistance in the ignition 1 voltage feed circuit to the SDM.
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Tests to see if there is an open or a high resistance in the ignition 1 voltage feed circuit to the SIR Fuse.
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Tests to see if there is an open or a high resistance in the SDM ground circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: SIR Schematics | ||||
1 | Did you perform the Diagnostic System Check - SIR? | -- | Go to Step 2 | |
2 |
Does the AIR BAG indicator flash 7 times? | -- | Go to Step 4 | Go to Step 3 |
3 | Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | -- | Go to Step 13 | -- |
4 | Note the AIR BAG indicator after it has flashed seven times. Does the AIR BAG indicator turn OFF after flashing seven times? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 5 |
Does the scan tool communicate with the IPC? | -- | Go to Step 6 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |
With a scan tool, observe the SIR data list display. Does the scan tool indicate that the ignition voltage is greater than the specified value? | 9 V | Go to Step 7 | Go to Step 8 | |
Does the scan tool indicate that the ignition voltage is greater than the specified value? | 16 V | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | Go to Step 12 | |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 | |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 | |
Test the ignition 1 voltage feed circuit to the SIR Fuse for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | |
12 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
