Circuit Description
When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) perform tests to diagnose critical malfunctions within itself. Next the SDM measures ignition positive voltage and the deployment loop voltages to make sure they are within their respective normal voltage ranges. Then the SDM proceeds with the RESISTANCE MEASUREMENT test. During 1 portion of the RESISTANCE MEASUREMENT test, the SDM does the following:
| • | Grounds the PASSENGER LOW terminal 8 through an internal current sink. |
| • | Connects the PASSENGER HIGH terminal 7 to an internal constant current source. This current produces proportional voltage drops in the deployment loop. |
| • | Measures the voltage difference between PASSENGER HIGH and PASSENGER LOW. |
| • | Calculates the resistance of the passenger deployment loop using the measured voltage. |
Conditions for Setting the DTC
| • | The driver and passenger deployment loops are not open. |
| • | The driver and passenger deployment loops are not shorted to voltage. |
| • | The driver and passenger deployment loops are not shorted to ground. |
| • | The passenger deployment loop resistance is more than 3.0 ohms. |
| • | The passenger deployment loop consists of the following components: |
| - | An inflatable restraint IP module |
| - | Harness wiring of CKT 1403 |
| - | Harness wiring of CKT 1404 |
| - | Connector terminal contact |
The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs once each ignition cycle when ignition positive voltage is within the normal operating voltage range.
Action Taken When the DTC Sets
| • | The SDM sets a diagnostic trouble code. |
| • | The SDM commands the instrument cluster in order to turn ON the AIR BAG warning lamp. |
Conditions for Clearing the MIL/DTC
The DTC will clear when one of the following conditions is met:
| • | Current DTC |
| The resistance of the passenger deployment loop is less than 3.0 ohms and the ignition switch is cycled. |
| • | History DTC |
| - | You issue a scan tool CLEAR CODES command. |
| - | Once 250 malfunction free ignition cycles have occurred. |
When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.
Diagnostic Aids
A poor connection can cause an intermittent condition. Check the following for a poor connection:
| • | The inflatable restraint IP module harness connector terminals A and B. |
| • | The SDM terminals 7 and 8. |
| • | The wire to terminal connections in CKT 1403. |
| • | The wire to terminal connections in CKT 1404. |
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:
-
This test checks for proper contact or corrosion of the inflatable restraint IP module yellow 2-way connector.
-
This test isolates the malfunction to one side of the inflatable restraint IP module yellow 2-way connector.
-
This test checks for proper contact or corrosion of the SDM connector.
-
This test determines whether the malfunction is in CKT 1403.
-
This test determines whether the malfunction is in CKT 1404.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | |
Are the terminals damaged or corroded? | -- | Go to Step 3 | Go to Step 5 | |
3 | Replace the inflatable restraint IP module yellow 2-way IP harness connector. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 4 | -- |
4 | Check for proper connection at terminals A and B on the inflatable restraint IP module yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 6 | Go to Step 20 |
5 | Check for proper connection at terminals A and B on the inflatable restraint IP module yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 6 | Go to Step 7 |
6 | Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement . Is the repair complete? | -- | Go to Step 20 | -- |
7 |
Is DTC B1115 current? | -- | Go to Step 9 | Go to Step 8 |
8 |
Is the repair complete? | -- | Go to Step 20 | -- |
Is DTC B1115 current? | -- | Go to Step 11 | Go to Step 10 | |
10 |
Is the repair complete? | -- | Go to Step 20 | -- |
Is the harness connector damaged or corroded? | -- | Go to Step 12 | Go to Step 14 | |
12 | Replace the inflatable restraint sensing and diagnostic module (SDM) harness connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 13 | -- |
13 | Check for proper connection at terminals 8 and 7 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 15 | Go to Step 20 |
14 | Check for proper connection at terminals 8 and 7 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 15 | Go to Step 16 |
15 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 20 | -- |
Is the resistance less than the specified value? | 0.5 ohms | Go to Step 18 | Go to Step 17 | |
17 | Repair the high resistance condition in CKT 1403. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 20 | -- |
Is the resistance reading within the specified values? | 0.5 ohms | Go to Step 19 | ||
19 | Repair the high resistance condition in CKT 1404. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 20 | -- |
20 | Reconnect all the SIR components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to Step 21 | -- |
21 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | -- |
