Circuit Description
The inflatable restraint sensing and diagnostic 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 and system voltage 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 then goes into Continuous Monitoring mode. Refer to On-Vehicle Service for enable/disable procedures.
Conditions for Setting the DTC
DTC B1045 will set once the following conditions are met. This test is run during the SDM Turn-ON tests.
| • | The ignition is within normal operating voltage range. |
| • | An internal fault in the driver side impact sensor (SIS). |
| • | An open circuit condition in the driver side impact sensor (SIS) circuit. |
| • | A short circuit condition in the driver side impact sensor (SIS) circuit. |
| • | A short to ground condition in the driver side impact (SIS) circuit. |
| • | A short to voltage condition in the driver side impact sensor (SIS) circuit. |
The driver side impact sensor (SIS) loop consists of the following components:
| • | The inflatable restraint side impact sensor (LH) . |
| • | The harness wiring of CKT 2131. |
| • | The harness wiring of CKT 2132. |
| • | The connector terminal contact. |
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 Current DTC B1045 to set are no longer existing, History DTC B1045 will set. History DTC B1045 may be cleared using the scan tool.
Diagnostic Aids
An inflatable restraint driver side impact sensor (SIS) circuit short to ground can cause an intermittent condition. Inspect CKT 2131 and CKT 2132 carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC B1045 Table is essential to make sure that the replacement SDM will not be damaged.
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 numbers below refer to the step numbers on the diagnostic table:
-
This test determines if the sensor is damaged.
-
This test checks for proper contact or corrosion of the yellow 2-way connector.
-
This test checks for proper contact or corrosion of the SDM harness connector.
-
This test checks for an open circuit or high resistance condition in CKT 2132
-
This test checks for an open circuit or high resistance condition in CKT 2131.
-
This test checks for a short between CKT 2131 and CKT 2132.
-
This test checks for a short to ground condition in CKT 2131.
-
This test checks for an short to ground condition in CKT 2132.
-
This test checks for a short to voltage condition in CKT 2132.
-
This test checks for a short to voltage condition in CKT 2131.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is the sensor damaged or are the sensor terminals damaged or corroded? | -- | |||
3 | Replace the inflatable restraint side impact sensor (LH). Refer to Inflatable Restraint Side Impact Sensor Replacement . Are the repairs complete? | -- | -- | |
Check for proper connection at terminals A and B on the body harness side of the inflatable restraint side impact sensor (LH) yellow 2-way connector. Are the terminals damaged or corroded? | -- | |||
5 | Check for proper connection at terminals A and B on the body harness side of the inflatable restraint side impact sensor (LH) yellow 2-way connector. Are the terminals damaged or corroded? | -- | ||
6 | Replace the inflatable restraint side impact sensor (LH) yellow 2-way body harness connector. Refer to Wiring Repair . Are the repairs complete? | -- | -- | |
Is the harness connector damaged or corroded? | -- | |||
8 | Replace the SDM connector. Refer to Wiring Repair . Are the repairs complete? | -- | -- | |
9 | Check for proper connection at terminals 41 and 42 on the SDM. Are the terminals damaged or corroded? | -- | ||
10 | Check for proper connection at terminals 41 and 42 on the SDM. Are the terminals damaged or corroded? | -- | ||
11 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | -- | |
Is the resistance reading within the specified values? | 0-0.5 ohms | |||
13 | Repair the high resistance condition in CKT 2132. Are the repairs complete? | -- | -- | |
Is the resistance reading within the specified values? | 0-0.5 ohms | |||
15 | Repair the high resistance condition in CKT 2131. Are the repairs complete? | -- | -- | |
Is the resistance reading within the specified values? | 0-0.5 ohms | |||
17 | Repair the short circuit condition between CKT 2131 and CKT 2132. Are the repairs complete? | -- | -- | |
Is the resistance reading less than the specified value? | OL | |||
19 | Repair the short to ground condition in CKT 2131. Are the repairs complete? | -- | -- | |
Is the resistance reading less than the specified value? | OL | |||
21 | Repair the short to ground condition in CKT 2132. Are the repairs complete? | -- | -- | |
Is the voltage reading less than the specified value? | 1 V | |||
23 | Repair the short to voltage condition in CKT 2132. Are the repairs complete? | -- | -- | |
Is the voltage reading less than the specified value? | 1 V | |||
25 | Repair the short to voltage condition in CKT 2131. Are the repairs complete? | -- | -- | |
26 |
Are the repairs complete? | -- | -- | |
27 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | Go to Integrity Check | |
28 | Reconnect all the SIR components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- | |
29 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | -- |
