Circuit Description
The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts the vehicle velocity changes to an electrical signal. The SDM processes the generated electrical signal and compares it to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to signals stored in memory. When 2 of the generated signals exceed the stored values, the SDM will cause the current in order to flow through the frontal inflator modules. This deploys the air bags and causes DTC B1151 and DTC B1152 to set.
Conditions for Setting the DTC
The SDM detects a frontal crash, up to 30 degrees off the centerline of the vehicle, of sufficient force in order to warrant deployment of the air bags.
Action Taken When the DTC Sets
| • | The SDM sets a DTC B1151 and DTC B1152. |
| • | The SDM commands the instrument cluster in order to turn ON the AIR BAG warning lamp. |
| • | The SDM records crash data. |
| • | The SDM sends a message over the serial data line Class 2. |
Conditions for Clearing the MIL/DTC
A scan tool CLEAR DTCs command is received by the SDM.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
If the inflator modules have not deployed, DTC B1151 and DTC B1152 may have set falsely.
-
If DTC B1151 and DTC B1152 has set with no signs of frontal impact, the DTC has set falsely.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | |
2 | Connect a scan tool to the data link connector (DLC). Is DTC B1153 set? | -- | Go to Step 3 | |
Turn the ignition switch to the OFF position. Did the frontal inflator modules deploy? | -- | Go to Step 5 | Go to Step 4 | |
Inspect the front of the vehicle and the undercarriage for signs of impact. Are there signs of impact? | -- | Go to Step 5 | Go to Step 6 | |
5 | Replace components and perform inspections as required following an accident. Refer to Repairs and Inspections Required After a Collision . Have the appropriate inspections and repairs been made? | -- | Go to Step 7 | -- |
6 | Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Is the repair complete? | -- | Go to Step 7 | -- |
7 | Reconnect all the SIR system components. Ensure that all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- |
