DTC 22

Circuit Description
When the ignition switch is turned ON, the sensing and diagnostic module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, Ignition 1 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 3 is grounded through a current sink. The driver current source is connected to the driver high terminal 2 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 clockspring, the harness wiring, and the connector terminal contacts.

DTC 22
DTC 22 will set when the resistance of the driver deployment loop is below a specified value. The test is run once each ignition cycle during the resistance measurement test when the following conditions exist:
- No higher priority faults are detected when the ignition is turned ON.
- Ignition 1 voltage is below a specified value.

When DTC 22 is set, the SDM will turn on the AIRBAG indicator.

DTC 22 will clear when the ignition switch is turned OFF or 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 clockspring or a faulty shorting bar in the clockspring 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.

Test Description
The numbers below refer to steps on the diagnostic table.
3. Refer to the first caution below.
15. Refer to the third caution below.

Steps 1 - 9:

Steps 10 - 16:

DTC 22 - Driver Deployment Loop Resistance Low

CAUTION: The sensing and diagnostic module (SDM) can maintain sufficient voltage to deploy the airbags for 10 minutes after the ignition is OFF and the fuse has been removed. If the airbags are not disconnected, do not begin service until 10 minutes have passed after disconnecting power to the SDM. Otherwise, injury could result.

CAUTION: Never measure the resistance of an inflator module with an ohmmeter. The ohmmeter battery could unexpectedly deploy the airbag which would created the possibility of severe injury and would require the replacement of otherwise useable components.

CAUTION: During service procedures, be very careful when handling the SDM. Never strike or jar the SDM. Never power the supplemental inflatable restraint (SIR) system when the SDM is not rigidly attached to the vehicle. All SDM mounting bolts must be carefully tightened, and the SDM arrow must be pointing toward the front of the vehicle to ensure proper operation of the SIR system. The SDM could be activated if it is powered when it is not rigidly attached to the vehicle, resulting in unexpected deployment and possible injury.