Circuit Description
When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests in order to diagnose the critical malfunctions within the module. Upon passing these tests the ignition positive voltage, 23 VLR and the deployment loop voltages are measured in order to ensure they are within their respective normal voltage ranges. The SDM monitors the voltages at the DRIVER FRONTAL LOW terminal 9 and the PASSENGER FRONTAL LOW terminal 8 in order to detect shorts to ground in the inflator module circuits.
Conditions for Setting the DTC
| • | The driver and passenger frontal deployment loops are not open. |
| • | The voltage at the DRIVER FRONTAL LOW terminal 9 or the PASSENGER FRONTAL LOW terminal 8 is less than 2.2 volts for 500 milliseconds. |
The following tests check for this DTC. The following tests occur when the ignition positive voltage is within the normal operating voltage range:
| • | POWER-ON |
| When the malfunction is detected in this test, the RESISTANCE MEASUREMENT test will not be performed. |
| • | CONTINUOUS MONITORING |
Action Taken When the DTC Sets
| • | The SDM sets a diagnostic trouble code. |
| • | The SDM commands the instrument panel cluster (IPC) 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 voltage measured at DRIVER FRONTAL LOW and PASSENGER FRONTAL LOW is above 2.2 volts for 500 milliseconds or the ignition switch is cycled. |
| • | History DTC |
| - | You issue a scan tool CLEAR CODES command. |
| - | 250 malfunction free ignition cycles occur. |
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 short-to-ground in the inflatable restraint steering wheel module circuit or the passenger frontal inflator module circuit can cause an intermittent condition. Moving wires while monitoring the DRIVER SENSELO and the PASSENGER SENSELO may help in order to locate the fault. Inspect the following circuits carefully for cutting or chafing:
| • | CKT 347 |
| • | CKT 348 |
| • | CKT 1403 |
| • | CKT 1404 |
The diagnostic table directs the technician in order to note the entry value of the DRIVER SENSELO and the PASSENGER SENSELO. Noting the value of the DRIVER SENSELO and the PASSENGER SENSELO during diagnosis can be helpful in determining if an intermittent condition exists. An intermittent open in the inflatable restraint steering wheel module coil could also set this DTC. In order to test for a bad inflatable restraint steering wheel module coil, monitor the DRIVER SENSELO while you turn the steering wheel back and forth using the ignition switch in the RUN position. If the DRIVER SENSELO changes while you are turning the steering wheel, a malfunction in the inflatable restraint steering wheel module coil is likely.
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 the DRIVER FRONTAL LOW voltage measured by the inflatable restraint sensing and diagnostic module (SDM) and if the malfunction is occurring now.
-
This test isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector.
-
This test determines whether the malfunction is due to the inflatable restraint steering wheel module or the module coil.
-
This test determines whether the malfunction is in CKT 347.
-
This test determines whether the malfunction is in CKT 348.
-
This test isolates the malfunction to one side of the inflatable restraint IP module, yellow 2-way 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? | -- | ||
Is DRIVER SENSELO less than the specified value? | 2.2 V | |||
Is DRIVER SENSELO less than the specified value? | 2.2 V | |||
Is DRIVER SENSELO less than the specified value? | 2.2 V | |||
5 |
Have the repairs been completed? | -- | -- | |
6 |
Have the repairs been completed? | -- | -- | |
Is the resistance reading less than the specified value? | OL | |||
8 | Repair a short-to-ground condition in CKT 347. Have the repairs been completed? | -- | -- | |
Using J 39200 DMM, measure the resistance on the SDM harness connector between terminals 9 and 18 (ground). Is the resistance reading less than the specified value? | OL | |||
10 | Repair a short-to-ground condition in CKT 348. Have the repairs been completed? | -- | -- | |
Is PASS. SENSELO less than the specified value? | 2.2 V | |||
12 |
Have the repairs been completed? | -- | -- | |
Is the resistance less than the specified value? | OL | |||
14 | Repair a short-to-ground condition in CKT 1404. Have the repairs been completed? | -- | -- | |
Using J 39200 , measure the resistance on the SDM harness connector between terminals 7 and 18 (ground). Is the resistance less than the specified value? | OL | |||
16 | Repair a short-to-ground condition in CKT 1403. Have the repairs been completed? | -- | -- | |
17 |
Has the intermittent short-to-ground been found and repaired? | -- | -- | |
18 |
Have all the SIR components been reconnected and properly mounted? | 2.2 V | -- |
