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. Upon passing these tests, and if the energy reserve is charged up, the firing transistors are tested. The SDM service wait time is 1 minute. Refer to On-Vehicle Service for enable/disable procedures.
Conditions for Setting the DTC
- Neither of the two side air bag circuits is open.
- The ignition is within normal operating voltage range.
- The measured leakage currents to ground in the driver side air bag deployment loop are above a specified value.
DTC 75 will set once these conditions are met. This test is run during the SDM Turn-ON tests.
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.
Diagnostic Aids
An inflatable restraint steering wheel module circuit short-to-ground or a short circuit between the communication signal return line of the LH or RH inflatable restraint Side Impact Sensor can cause an intermittent condition. Inspect CKTs XB100 and AB11 carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC 75 Table is essential to make sure that the replacement SDM will not be damaged. Also inspect CKTs XB42 and XM430 carefully for cutting and/or chafing.
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:
-
This test isolates the malfunction to one side of the inflatable restraint driver seat module yellow harness.
-
This test isolates the malfunction to one side of the inflatable restraint driver seat harness connector located under the LH front seat track cover.
-
This test determines whether the malfunction is in CKT AB11.
-
This test determines whether the malfunction is in CKT XB100.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic Check performed? | -- | ||
Is a current DTC 75 displayed? | -- | |||
3 | Replace the inflatable restraint driver seat module. Refer to Inflatable Restraint Seat Module Replacement - Driver . Is the replacement complete? | -- | -- | |
Is a current DTC 75 displayed? | -- | |||
5 | Replace the inflatable restraint driver seat harness. Is the replacement complete? | -- | -- | |
6 |
Is the harness connector damaged or corroded? | -- | ||
7 | Replace the IP harness. Are the repairs complete? | -- | -- | |
8 | Check for proper connection at terminals 10 and 11 on the SDM. Are the terminals damaged or corroded? | -- | ||
9 | Check for proper connection at terminals 10 and 11 on the SDM. Are the terminals damaged or corroded? | -- | ||
10 | 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 measured resistance less than the specified value? | OL | |||
12 | Repair the short to ground condition in CKT AB11. Is the repair complete? | -- | -- | |
Use the J 39200 to measure the resistance on the SDM harness connector from terminal 10 to terminal 7 (ground). Is the measured resistance less than the specified value? | OL | Go to Integrity Check | ||
14 | Repair the short to ground condition in CKT XB100. Is the repair complete? | -- | -- | |
15 | Reconnect all of the SIR components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- | |
16 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | -- |
