Circuit Description
When the ignition switch is first turned to RUN, the IGN 1 Fuse applies battery voltage to the AIR BAG warning lamp that is connected to AIR BAG INDICATOR CONTROL, terminal 7. The AIR BAG Fuse applies battery voltage to the Ignition Positive Voltage input, terminal 10. The inflatable restraint sensing and diagnostic module (SDM) responds by flashing the AIR BAG warning lamp 7 times. If Ignition Positive Voltage is outside of the normal operating voltage range (8.2 volts - 17.1 volts), the AIR BAG warning lamp will come ON solid with no DTCs set.
Diagnostic Aids
In order to disable the shorting bar from terminal 6 to terminal 7 inside the inflatable restraint sensing and diagnostic module (SDM) harness connector, the following 2 conditions must be met:
| • | The SDM harness connector must be properly connected to the SDM. |
| • | The connector position assurance (CPA) must be properly installed in the SDM harness connector. |
When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616 Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents in Wiring Systems. When a wire, connector or terminal repair is requested, use the J-38125 Terminal Repair Kit and refer to Wiring Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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This test checks for sufficient Ignition Positive Voltage applied to the SDM.
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This test checks for excessive Ignition Positive Voltage applied to the SDM.
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This test checks for a properly installed CPA.
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This test determines if the SDM is turning on the AIR BAG warning lamp.
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This test checks for a damaged shorting bar.
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This test determines whether the malfunction is a short to ground in CKT 358.
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This test checks for a short between CKTs 358 and 1851.
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This step checks to see if the AIR BAG Fuse is OK. An open AIR BAG Fuse would cause the AIR BAG warning lamp to come on steady.
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This test checks whether a short to ground caused the AIR BAG Fuse to open.
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This test determines whether the short to ground is due to a short in the wiring or internal to the SDM.
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This test determines whether the short to ground is due to a short in the wiring or internal to the inflatable restraint IP module switch.
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This test checks for a disconnected SDM.
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This test checks for an open in the Igntion Positive Voltage circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | |
Is Ignition Positive Voltage more than the specified value? | 8.2 V | Go to Step 3 | Go to Step 14 | |
Is Ignition Positive Voltage more than the specified value? | 17.1 V | Go to Charging System Check in Engine Electrical | Go to Step 4 | |
Is the CPA properly installed? | -- | Go to Step 6 | Go to Step 5 | |
5 | Properly install the CPA. Is the repair complete? | -- | -- | |
Does the AIR BAG warning lamp come ON steady? | -- | Go to Step 7 | ||
Is the shorting bar damaged or corroded? | -- | Go to Step 8 | Go to Step 9 | |
8 | Replace the SDM harness connector. Is the repair complete? | -- | Go to Step 30 | -- |
Is the resistance reading less than the specified value? | OL | Go to Step 10 | Go to Step 13 | |
Is the resistance reading less than the specified value? | OL | Go to Step 12 | Go to Step 11 | |
11 | Repair a short to ground condition in CKT 358. Is the repair complete? | -- | Go to Step 30 | -- |
12 |
Is the repair complete? | -- | Go to Step 30 | -- |
13 | Service the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console. Is the repair complete? | -- | Go to Step 30 | -- |
Is the AIR BAG Fuse good? | -- | Go to Step 22 | Go to Step 15 | |
Is the AIR BAG Fuse good? | -- | Go to Step 21 | Go to Step 16 | |
Is the measured resistance less than the specified value? | OL | Go to Step 17 | Go to Step 27 | |
17 | Does this vehicle have a inflatable restraint IP module switch? | -- | Go to Step 18 | Go to Step 20 |
Is the AIR BAG Fuse good? | -- | Go to Step 19 | Go to Step 20 | |
19 |
Has the inflatable restraint IP switch been replaced and the AIR BAG Fuse installed? | -- | Go to Step 30 | -- |
20 |
Is the repair complete? | -- | Go to Step 30 | -- |
21 | Install the AIR BAG Fuse. Is the repair complete? | -- | Go to Step 30 | -- |
Inspect the SDM harness connector. Is the connector securely connected to the SDM? | -- | Go to Step 24 | Go to Step 23 | |
23 |
Is the repair complete? | -- | Go to Step 30 | -- |
24 |
Is the SDM harness connector terminal damaged or corroded? | -- | Go to Step 25 | Go to Step 26 |
25 | Replace the SDM harness connector. Refer to Wiring Repair . Is the repair complete? | -- | Go to Step 30 | -- |
26 | Inspect the SDM terminals for damage or corrosion. Are any terminals damaged or corroded? | -- | Go to Step 27 | Go to Step 28 |
27 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Is the repair complete? | -- | Go to Step 30 | -- |
Measure the resistance from the SDM harness connector terminal 10 to each terminal of the AIR BAG Fuse fuseholder. Is either resistance reading within the specified values? | 0-5 ohms | Go to Step 29 | ||
29 | Repair an open condition in CKT 1139. Is the repair complete? | -- | Go to Step 30 | -- |
30 |
Have all the SIR components been reconnected and properly mounted? | -- | -- |
