Circuit Description
When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.
The test ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deploy loops.
The SDM inspects the wiring connection to the passenger air bag module by letting the infinitesimal current flow through the internal circuit and verify the resistances. If the resistance is in the 2 kilo ohms between 10 kilo ohms, the defect may occur depending upon the SDM. The normal resistance is over 10 kilo ohms.
Conditions for Setting the DTC
| • | The belt pretensioner wiring of driver high is shorted to battery wiring. |
| • | The belt pretensioner wiring of driver low is shorted to battery wiring. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
|
Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section. | ||||
1 | Perform the Diagnostic System Check - SIR. Is the Diagnostic System Check - SIR complete? | -- | Go to Step 2 | |
2 |
The capacitor supplies reserve power to deploy the driver seat belt pretensioner even if the battery has been disconnected. Is there any visible damage to the SIR wiring harness? | -- | Go to Step 3 | Go to Step 4 |
3 |
Is the repair complete? | -- | -- | |
4 |
The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the driver seat belt pretensioner module. Is the voltage greater than the specified value? | 0 V | Go to Step 3 | Go to Step 5 |
5 |
Is DTC 012 still shown as a current fault? | -- | Go to Step 6 | System OK |
6 |
Is the repair complete? | -- | -- | |
