Circuit Description
When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, ignition and deployment loop voltages are measured to ensure that they are within their respective normal voltage ranges. The SDM then proceeds with the resistance measurement test. Driver low terminal A3 is grounded through a current sink, and the driver current source is connected to the driver high terminal A6 to allow a known amount of current to flow. By monitoring the voltage difference between driver high and driver low, the SDM calculates the combined resistance of the driver inflator module, the clock spring, the harness wiring, and the connector terminal contacts.
Conditions for Setting the DTC
| • | Resistance of the driver deployment loop is less than 1.7 ohms for 500 milliseconds. |
| • | Ignition voltage is within a specified value. |
Action Taken When the DTC Sets
The SDM will turn on the AIRBAG indicator and set a diagnostic trouble code DTC 22.
Conditions for Clearing the DTC
| • | Resistance of the driver deployment loop is higher than or equal to 1.7 ohms for 500 milliseconds. |
| • | Turn OFF the ignition switch. |
| • | The scan tool CLEAR CODES command is received. |
Diagnostic Aids
An intermittent condition is likely to be caused by a short between driver high and driver low or between driver high and passenger low. This condition could also be caused by a faulty clock spring or a faulty shorting bar in the clock spring steering column connector. The test for this DTC is run only while the AIRBAG indicator is performing the turn-on test. When a scan tool CLEAR CODES command is issued and the malfunction is still present, the DTC will not reappear until the next ignition cycle.
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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Perform the Diagnostic System Check - SIR. Is the Diagnostic System Check - SIR complete? | -- | Go to Step 2 | |
2 |
Is the DTC 16 also currect? | -- | Go to Step 3 | Go to Step 4 |
3 |
Did you complete the repair? | -- | Go to the Diagnostic System Check - SIR | -- |
4 |
Is a faulty component, connector, terminal, or wire detected? | -- | Go to Step 5 | Go to Step 6 |
5 |
Did you complete the repair? | -- | -- | |
6 | Visually check the SDM connector terminals A6 and A7 for shorted terminals or wires. Is a problem found? | -- | Go to Step 7 | Go to Step 8 |
7 |
Did you complete the repair? | -- | -- | |
8 | With the SDM disconnected, use an ohmmeter to check the SDM harness connector for a short between terminal A6, driver high, and terminal A8, passenger low. Refer to Diagnostic Illustration 10 in SIR Diagnostic Illustrations . Is there a short between driver high and passenger low? | 0 ohms | Go to Step 9 | Go to Step 10 |
9 |
Did you complete the repair? | -- | -- | |
10 |
Refer to Diagnostic Illustration 11 in SIR Diagnostic Illustrations . Is there a short circuit between the driver high and driver low circuits? | 0 ohms | Go to Step 12 | Go to Step 11 |
11 |
Is the DTC 22 still current? | -- | Go to Step 15 | System OK |
12 |
Refer to Diagnostic Illustration 11 in SIR Diagnostic Illustrations . Is there a short circuit between the driver high and the driver low circuits? | 0 ohms | Go to Step 14 | Go to Step 15 |
13 |
Did you complete the repair? | -- | -- | |
14 | Repair the shorted driver high and driver low wire between the SDM and the clock spring. Did you complete the repair? | -- | -- | |
15 |
| -- | -- |
