Supplemental Inflatable Restraint (SIR)

Test Q: DTC 26 Driver Initiator Circuit Open:

Supplemental Inflatable Restraint (SIR):

OPERATION:
When there is an open in the Driver Inflator Module or the SIR Coil Assembly, the resistance between "Driver Side High" terminal "B9" and "Driver Side Low" terminal "B8" increases. This causes a larger voltage drop from the "Driver Side High" to the "Driver Side Low" across a resistor inside the DERM which connects these two terminals together. The increase in the voltage difference between "Driver Side High" and "Driver Side Low" is detected by the DERM during the "Continuous Monitoring" tests and DTC 26 is set.

Test Condition: Tested every 100 milliseconds during the "Continuous Monitoring" tests.

Failure Conditions: DTC 26 will set when the voltage difference between "Driver Side High" terminal "B9" and "Driver Side Low" terminal "B8" is above or equal to a specified value for 500 milliseconds.

Action Taken: DERM turns "ON" the "AIR BAG" warning lamp and sets a Diagnostic Trouble Code.

Conditions to Clear: DTC 26 will clear when the voltage difference between "Driver Side High" terminal "B9" and "Driver Side Low" terminal "B8" is below a specified value for 500 milliseconds.

POSSIBLE CAUSES:
Test Description: Number(S) below refer to circled number(S) on the diagnostic chart.
1. This test checks whether the DERM has set the Diagnostic Trouble Code falsely.
2. This test determines whether the malfunction is in the Driver Inflator Module or the SIR Coil Assembly.

DIAGNOSTIC AIDS:
This diagnostic trouble code will only set when there is an improper connection of either the yellow 2-way connector near the base of the steering column or the yellow 2-way connector at the top of the steering column, an open SIR coil assembly or an open inflator module.