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. Upon passing these tests IGNITION, 23VLR and the deployment loop voltages are measured to make sure they are within their respective normal voltage ranges. The SDM monitors the voltages at Driver Frontal Low terminal 2 and Passenger Frontal Low terminal 3 to detect shorts-to-B+ in the inflator module circuits.
Conditions for Setting the DTC
| • | The voltage at Passenger Frontal Low terminal 3 is less than 3.8 volts. |
| • | The voltage at Driver Frontal Low terminal 2 is more than 3.8 volts for 500 milliseconds. |
The CONTINUOUS MONITORING test checks for this DTC. This test occurs when IGNITION is within the normal operating voltage range.
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 DTC-The voltage at Driver Frontal Low terminal 2 is less than 3.5 volts for 500 milliseconds. |
| • | History DTC |
| - | You issue a scan tool CLEAR CODES command. |
| - | Once 250 malfunction free ignition cycles have occurred. |
Diagnostic Aids
A short-to-B+ in the inflatable restraint steering wheel module circuit can cause an intermittent condition. Inspect CKT 347 and CKT 348 carefully for cutting or chafing. The diagnostic table directs the technician to note the entry value of DRIVER FRONTAL SENSELO. Comparing the value of DRIVER FRONTAL SENSELO can be helpful in determining if an intermittent condition exists.
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:
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This test determines the driver frontal air bag low voltage measured by the inflatable restraint sensing and diagnostic module (SDM).
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This test isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector.
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This test determines whether the malfunction is due to the inflatable restraint steering wheel module or the module coil.
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This test determines whether the malfunction is in CKT 347.
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This test determines whether the malfunction is in CKT 348.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Has the DRIVER FRONTAL SENSELO been read and recorded on the repair order? | -- | -- | ||
Is DRIVER FRONTAL SENSELO more than the specified value? | 3.8 V | |||
Is DRIVER FRONTAL SENSELO more than the specified value? | 3.8 V | |||
5 |
Are the repairs complete? | -- | -- | |
6 |
Are the repairs complete? | -- | -- | |
Is the measured voltage less than the specified value? | 1 V | |||
8 | Repair a short to voltage condition in CKT 347. Are the repairs complete? | -- | -- | |
Measure the voltage on the SDM harness connector from terminal 2 to terminal 7 (ground). Is the resistance reading less than the specified value? | 1 V | Go to Integrity Check | ||
10 | Repair a short to voltage condition in CKT 348. Are the repairs complete? | -- | -- | |
11 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- | |
12 | Clear all the SIR DTCs. Have all the SIR DTCs been cleared? | -- | -- |
