Circuit Description
When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM then measures IGNITION 1 voltage and the deployment loop voltages to verify they are within their respective normal voltage ranges. The SDM then proceeds with the RESISTANCE MEASUREMENT test. During one portion of the RESISTANCE MEASUREMENT test, the SDM performs the following steps:
| • | Grounds the PASSENGER SIDE LOW terminal 4 through an internal current sink. |
| • | Connects the PASSENGER SIDE HIGH terminal 1 to an internal constant current source. |
| This current produces proportional voltage drops in the deployment loop. |
| • | Measures the voltage difference between PASSENGER SIDE HIGH and PASSENGER SIDE 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 passenger deployment loop is not shorted to ground. |
| • | The passenger deployment loop resistance is less than 1.4 ohms. |
Action Taken When the DTC Sets
The SDM turns ON the AIR BAG warning lamp.
Conditions for Clearing the DTC
| • | Current DTC |
| The resistance of the passenger deployment loop is more than 1.4 ohm and the ignition switch is cycled. |
| • | History DTC |
| - | You issue a scan tool CLEAR CODES command. |
| - | After 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
The following may cause an intermittent condition:
| • | A short circuit between CKT 1403 and CKT 347 |
| • | A short circuit between CKT 1403 and CKT 348 |
| • | A short circuit between CKT 1403 and CKT 1404 |
| • | A malfunctioning shorting bar on the inflatable restraint IP module connector. |
The diagnostic table directs the technician to note the entry value of PASSENGER RESISTANCE. Comparing the value of PASSENGER RESISTANCE over multiple ignition cycles may be helpful in determining if an intermittent condition exists.
When measurements are requested in this table, use the J 39200 Digital Multimeter 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 Intermittent Conditions and Poor Connections in Wiring Systems. When a wire, connector or terminal repair is requested, use the J-38125 Terminal Repair Kit. Refer to Wiring Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This test determines the deployment loop resistance measured by the SDM.
-
This test isolates the malfunction to one side of the inflatable restraint IP module yellow 2-way connector.
-
This test inspects for proper contact or corrosion of the inflatable restraint IP module jumper connector.
-
This test determines whether the malfunction is due to the inflatable restraint IP module or the IP module jumper.
-
This test inspects for a short from CKTs 1403 to 1404.
-
This test inspects for a short from CKTs 1403 to 348.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | |
Is DTC B1022 also present? | -- | Go to Step 3 | Go to Step 4 | |
3 |
Is the repair complete? | -- | Go to Step 20 | -- |
4 |
Is PASSENGER RESISTANCE less than the specified value? | 1.4 ohms | Go to Step 6 | Go to Step 5 |
5 |
Is the repair complete? | -- | Go to Step 19 | -- |
Is PASSENGER RESISTANCE less than the specified value? | 1.4 ohms | Go to Step 15 | Go to Step 7 | |
Are the terminals damaged or corroded? | -- | Go to Step 8 | Go to Step 10 | |
8 | Repair the inflatable restraint IP module jumper harness. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Step 9 | -- |
9 | Inspect for proper connection at terminals A and B on the inflatable restraint IP module yellow 2-way pigtail connector. Are the terminals damaged or corroded? | -- | Go to Step 11 | Go to Step 19 |
10 | Inspect for proper connection at terminals A and B on the inflatable restraint IP module yellow 2-way pigtail connector. Are the terminals damaged or corroded? | -- | Go to Step 11 | Go to Step 12 |
11 | Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement . Is the repair complete? | -- | Go to Step 19 | -- |
Is PASSENGER RESISTANCE less than the specified value? | 1.4 ohms | Go to Step 14 | Go to Step 13 | |
13 |
Is the repair complete? | -- | Go to Step 19 | -- |
14 |
Is the repair complete? | -- | Go to Step 19 | -- |
Is the resistance less than the specified value? | OL | Go to Step 16 | Go to Step 17 | |
16 |
Is the repair complete? | -- | Go to Step 19 | -- |
Measure the resistance from the SDM harness connector terminal 1 to terminal 4. Is the resistance less than the specified value? | OL | Go to Step 18 | ||
18 | Repair the short from CKT 1403 to CKT 1404. Is the repair complete? | -- | Go to Step 19 | -- |
19 |
Have all SIR components been reconnected and properly mounted? | -- | Go to Step 20 | -- |
20 | Clear all SIR DTCs. Have all SIR DTCs been cleared? | -- | -- |
