Circuit Description
When you first turn the ignition switch to the ON position, the inflatable restraint sensing and diagnostic module (SDM) performs tests in order to diagnose critical malfunctions within itself. Upon passing these tests Ignition 1, 23VLR and the deployment loop voltages are measured in order to ensure that they are within their respective normal voltage ranges. The SDM monitors the voltages at Driver Pretensioner Low terminal 23 and Passenger Pretensioner Low terminal 11 in order to detect shorts to voltage in the pretensioner deployment circuits.
Conditions for Setting the DTC
The voltage at Driver Pretensioner Low terminal 23 or, Passenger Pretensioner Low terminal 11, is more than 4.0 volts for 500 milliseconds. The following tests check for this DTC. These tests occur when Ignition 1 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 (DTC). |
| • | The SDM commands the instrument cluster (IPC) to turn ON the AIR BAG warning lamp. |
Conditions for Clearing the MIL/DTC
| • | The voltage measured at Driver Pretensioner Low and Passenger Pretensioner Low is below 4.0 volts for 500 milliseconds. |
| • | The ignition switch is turned OFF. |
Diagnostic Aids
A short-to-voltage in the passenger pretensioner circuit or the driver pretensioner circuit can cause an intermittent condition. Moving wires while monitoring Driver Pretensioner Senselo and Passenger Pretensioner Senselo may help to locate the fault. Inspect CKT 2116, CKT 2117, CKT 2118, and CKT 2119 carefully for cutting or chafing. The diagnostic table directs the technician to note the entry value of Driver Pretensioner Senselo and Passenger Pretensioner Senselo. Noting the value of Driver Pretensioner Senselo and Passenger Pretensioner Senselo during diagnosis 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 General Electrical Diagnosis in Wiring Systems. 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 pretensioner voltage measured by the inflatable restraint sensing and diagnostic module (SDM) and if the malfunction is currently occurring.
-
This test isolates the malfunction to one side of the driver side air bag/pretensioner yellow 6-way connector.
-
This test isolates the malfunction to the jumper harness or the pretensioner.
-
This test determines whether the malfunction is in CKT 2118.
-
This test determines whether the malfunction is in CKT 2119.
-
This test isolates the malfunction to one side of the passenger side air bag/pretensioner yellow 6-way connector.
-
This test isolates the malfunction to the jumper harness or the pretensioner.
-
This test determines whether the malfunction is in CKT 2117.
-
This test determines whether the malfunction is in CKT 2116.
Notice: When DTC B1125 or DTC B1145 has been set it is necessary to replace the inflatable restraint Sensing and Diagnostic Module (SDM). Setting DTC B1125 or DTC B1145 will also cause DTC B1171 to set. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1171 will remain current. Make sure that the short to voltage condition is repaired prior to installing a replacement SDM to avoid damaging the SDM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | |
Is Driver Pretensioner Senselo less than the specified value? | 4.0 V | Go to Step 3 | Go to Step 19 | |
Is Driver Pretensioner Senselo less than the specified value? | 4.0 V | Go to Step 7 | Go to Step 4 | |
Is DTC B1145 current? | -- | Go to Step 5 | Go to Step 6 | |
5 |
Did you complete the replacement? | -- | Go to Step 20 | -- |
6 |
Did you complete the replacement? | -- | Go to Step 20 | -- |
Is the voltage reading more than the specified value? | 0.5 V | Go to Step 8 | Go to Step 9 | |
8 | Repair a short to voltage condition in CKT 2118. Refer to Wiring Repair . Did you complete the repair? | -- | Go to Step 20 | -- |
Using J 39200 DMM, measure the voltage between terminals 18 and 23 of the SDM harness connector. Is the voltage reading more than the specified value? | 0.5 V | Go to Step 10 | Go to Step 11 | |
10 | Repair a short to voltage condition in CKT 2119. Refer to Wiring Repair . Did you complete the repair? | -- | Go to Step 20 | -- |
Is Passenger Pretensioner Senselo more than the specified value? | 4.0 V | Go to Step 15 | Go to Step 12 | |
Is DTC B1145 current? | -- | Go to Step 13 | Go to Step 14 | |
13 |
Did you complete the replacement? | -- | Go to Step 20 | -- |
14 |
Did you complete the repair? | -- | Go to Step 20 | -- |
Is the voltage more than the specified value? | 0.5 V | Go to Step 16 | Go to Step 17 | |
16 | Repair a short to voltage condition in CKT 2117. Refer to Wiring Repair . Did you complete the repair? | -- | Go to Step 20 | -- |
Using J 39200 DMM, measure the voltage between terminals 12 and 18 of the SDM harness connector. Is the voltage more than the specified value? | 0.5 V | Go to Step 18 | Go to Step 19 | |
18 | Repair a short to voltage condition in CKT 2116. Refer to Wiring Repair . Did you complete the repair? | -- | Go to Step 20 | -- |
19 | An intermittent short to voltage condition caused DTC B1145 to set. Use the Diagnostic Aids for DTC B1145 and the DTC B1145 table to find the intermittent short to voltage. Has the intermittent short to voltage been found and repaired? | -- | Go to Step 20 | -- |
20 |
Have all the SIR components been reconnected and properly mounted? | 4.0 V | -- |
