Circuit Description
When the ignition is turned ON, the instrument panel cluster (IPC) flashes the AIR BAG indicator 7 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 of 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 Computer/Integrating Systems.
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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This step tests to see if the scan tool can communicate with the IPC.
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This step tests to see if the ignition 1 voltage is more than 9 volts.
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This step tests to see if the ignition 1 voltage is more than 16 volts.
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This step tests to see if the SDM connector is damaged or corroded.
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This step 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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This step tests to see if there is an open or a high resistance in the ignition 1 voltage feed circuit to the AIR BAG fuse.
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This step tests to see if there is an open or a high resistance in the SDM ground circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Connector End View Reference: SIR Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the AIR BAG indicator flash seven times? | -- | Go to Step 4 | Go to Step 3 |
3 | Replace the instrument panel cluster (IPC). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. 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 Computer/Integrating Systems | |
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 - Vehicle in Vehicle DTC Information | 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 AIR BAG 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 Control Module References in Computer/Integrating Systems for replacement, setup, and programming. 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 |
