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 critical malfunctions within the module. Upon passing these tests, the ignition positive voltage, the 23 VLR and the deployment loop voltages are measured in order to ensure that the voltages are within the respective normal voltage ranges. The SDM monitors the voltages at the DRIVER LOW terminal 3 and the PASSENGER LOW terminal 4 in order to detect shorts to ground in the inflator module circuits. The service wait time is 10 minutes. Refer to Disabling the SIR System or Enabling the SIR System for procedures.
Conditions for Setting the DTC
| • | The driver and passenger deployment loops are not open. |
| • | The passenger deployment loop is not shorted to voltage. |
| • | The voltage at PASSENGER LOW terminal 4 is more than 3.3 volts. |
| • | The voltage at DRIVER LOW terminal 3 is less than 3.3 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 DTC B1024 and also DTC B1071. |
| • | The SDM turns ON the AIR BAG Warning Indicator. |
Conditions for Clearing the MIL/DTC
DTC B1024 is a latched code. You may not clear a latched code. Repair the malfunction that set this DTC before you replace the SDM.
Diagnostic Aids
A short to ground in the inflatable restraint steering wheel module circuit may cause an intermittent condition. A DTC B1024 may be accompanied by DTC B1071. Carefully inspect CKT 347 and CKT 348 for cut or chafed wires. A careful inspection of the circuits and components indicated on the DTC B1024 table is essential in order to prevent damage to the replacement inflatable restraint sensing and diagnostic module (SDM). The diagnostic table directs the technician in order to note the entry value of the DRIVER SENSELO. Comparing the value of the DRIVER SENSELO may 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:
-
This step checks the driver side low voltage that was measured by the inflatable restraint sensing and diagnostic module (SDM). A reading of 3.3 V or more indicates that an intermittent condition may exist.
-
This step isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector.
-
This step determines if there is a malfunctioning inflatable restraint steering wheel module coil or if there is a malfunctioning inflatable restraint steering wheel module.
-
This step checks to see if there is a short to ground in CKT 347.
-
This step determines if there is a short to ground in CKT 348 or if there is a malfunctioning SDM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
|
Notice: When DTC B1018 or B1024 has been set it is necessary to replace the inflatable restraint Sensing and Diagnostic Module (SDM). Setting DTC B1018 or B1024 will also cause DTC B1071 to set. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1018 or B1024 and DTC B1071 will remain current. Make sure that the short to ground condition is repaired prior to installing a replacement SDM to avoid damaging the SDM. | ||||
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is the DRIVER SENSELO less than the specified value? | 3.3 V | Go to Diagnostic Aids | ||
Is DRIVER SENSELO less than the specified value? | 3.3 V | |||
Is DRIVER SENSELO less than the specified value? | 3.3 V | |||
5 |
Is the repair complete? | -- | -- | |
6 |
Is the repair complete? | -- | -- | |
Is the measured resistance less than the specified value? | OL | |||
8 |
Is the repair complete? | -- | -- | |
Use J 39200 DMM, measure the resistance between terminals 3 and 6 of the SDM wiring harness connector. Is the measured resistance less than the specified value? | OL | |||
10 |
Is the repair complete? | -- | -- | |
11 |
Have all the SIR components been reconnected and properly mounted? | 3.3 V | -- | |
