Circuit Description
When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then, the SDM provides input power to the inflatable restraint side impact sensor (SIS) - LF. When the input power is detected, the SIS responds by performing internal diagnostics. After that, the SIS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the SIS is powered up. The SIS will continually communicate a status message to the SDM. The SDM can reset the SIS by removing and applying power to it.
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
The SDM has received an ID message from the SIS that does not match the ID stored in the SDM memory.
Action Taken When the DTC Sets
| • | The SDM commands the AIR BAG indicator ON via Class 2 serial data. |
| • | The SDM attempts to reset the SIS. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used. |
| • | A history DTC will clear once 255 malfunction free ignition cycles have occurred. |
Diagnostic Aids
DTC B0079 is an indication that the incorrect SIS is installed in the vehicle. Check to make sure that the correct SIS is installed in the vehicle.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: SIR Schematics | |||
1 | Did you perform the Diagnostic System Check - SIR? | Go to Step 2 | |
2 |
Does the scan tool indicate that DTC B0079 is current? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Did you complete the replacement? | Go to Step 4 | -- |
4 |
Does the DTC reset? | Go to Step 2 | System OK |
