DTC 26

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 4 is grounded through a current sink. The driver current source is connected to the driver high terminal 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 harness wiring, and the connector terminal contacts.

DTC 26
DTC 26 will set when the resistance of the driver deployment loop is above a specified value for 500 milliseconds. The resistance is monitored during the deployment loop continuity test and continuous monitoring.

When DTC 26 is set, the SDM will turn on the AIRBAG indicator.

DTC 26 will clear when the voltage measured at driver low is below a specified value for 500 milliseconds or the ignition is turned OFF.

Diagnostic Aids
An intermittent condition is likely to be caused by a poor connection, either at the driver airbag or clockspring connectors or SDM terminals 2 and 3. An open wire in the driver deployment loop will also set DTC 26. To test for a faulty SIR clockspring, clear the DTCs, then turn the steering wheel back and forth with the ignition switch ON. If the AIRBAG indicator comes on and DTC 26 has set again, it is likely that the clockspring is faulty.

Test Description
The numbers below refer to steps on the diagnostic table.
4. This test establishes that the problem is either in the clockspring or the driver airbag.
7. Refer to the important below.
10. Refer to the first caution below.
14. Refer to the third caution below.

Steps 1 - 7:

Steps 8 - 12:

DTC 26 - Driver Deployment Loop Open

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 restraints (SIR) 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.

Important: Avoid deforming the terminals of the clockspring-to-airbag connector.