Circuit Description
The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) performs tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM monitors the six firing loops to detect leakage currents to ground in the frontal and side air bag inflator module and seat belt pretensioner circuits. The deployment loop resistances are measured to ensure they are within their respective normal resistance ranges. The SDM service wait time is 1 minute. Refer to On-Vehicle Service for enable/disable procedures.
Conditions for Setting the DTC
The driver side air bag deployment loop resistance is less than 1.1 ohms. The driver side air bag deployment loop consists of the following components:
| • | Inflatable restraint driver seat module. |
| • | Harness wiring of CKT XB100. |
| • | Harness wiring of CKT AB11. |
| • | Connector terminal contacts, including shorting bars. |
The deployment loop resistance test checks for this malfunction.
Action Taken When the DTC Sets
| • | The SDM sets a Diagnostic Trouble Code. |
| • | The SDM turns ON the AIR BAG warning lamp. |
Conditions for Clearing the DTC
Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the DTC to set are no longer existing, the DTC may be cleared using the scan tool. If the resistance in the inflatable restraint driver seat module circuit is greater than 1.1 ohms, a Current DTC 78 will change to a History DTC 78, which may be cleared using the scan tool.
Diagnostic Aids
The following can cause an intermittent condition:
| • | A short circuit between CKT XB100 and AB11. |
| • | A malfunctioning shorting bar in the inflatable restraint driver seat module. |
| • | A malfunctioning shorting bar on the inflatable restraint SDM harness connector above SDM harness connector terminals 10 and 11. |
| • | A malfunctioning shorting bar in the inflatable restraint driver seat yellow 2-way electrical connector. |
| • | A malfunctioning shorting bar in the yellow 2-way in-line connector C208. |
Inspect CKTs XB100 and AB11 carefully for cutting and/or chafing. The diagnostic table directs the technician to note the value of LH SIDE AIR BAG RESIST. Comparing the value of LH SIDE AIR BAG RESIST. over multiple ignition cycles can be helpful in determining if an intermittent condition exists.
When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .
Test Description
The following numbers refer to the step numbers on the diagnostic table:
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This test determines the deployment loop resistance measured by the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM).
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This test isolates the malfunction to one side of the inflatable restraint driver seat module 2-way integral connector.
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This test isolates the malfunction to one side of the inflatable restraint driver seat harness located under the LH front seat track cover.
-
This test checks for a short in CKT AB11 to XB100.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic Check performed? | -- | ||
Has LH SIDE AIR BAG RESIST. been read and recorded on the repair order? | -- | -- | ||
Is LH SIDE AIR BAG RESIST. less than the specified value? | 1.1 ohms | |||
4 | Replace the inflatable restraint driver seat module. Refer to Inflatable Restraint Seat Module Replacement - Driver . Is the replacement complete? | -- | -- | |
Is the driver side air bag deployment loop resistance less than the specified value? | 1.1 ohms | |||
6 | Replace the inflatable restraint driver seat harness. Is the replacement complete? | -- | -- | |
7 |
Is the harness connector damaged or corroded? | -- | ||
8 | Replace the IP harness. Are the repairs complete? | -- | -- | |
9 | Check for proper connection at terminals 10 and 11 on the SDM. Are the terminals damaged or corroded? | -- | ||
10 | Check for proper connection at terminals 10 and 11 on the SDM. Are the terminals damaged or corroded? | -- | ||
11 | Replace the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement . Are the repairs complete? | -- | -- | |
Is the resistance reading within the specified values? | 0-0.5 ohms | Go to Integrity Check | ||
13 | Repair the short circuit between CKT AB11 and CKT XB100. Is the repair complete? | -- | -- | |
14 | Reconnect all of the SIR components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- | |
15 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | -- |
