Supplemental Inflatable Restraint (SIR)

Test M: DTC 23 Driver Initiator Circuit Voltage High:

Supplemental Inflatable Restraint (SIR):

OPERATION:
During normal, non-deployment operation of the SIR system, a small amount of current flows through both the Driver and Passenger Deployment Loops. The Diagnostic Resistors within the Dual Pole Arming Sensor and the Discriminating Sensors along with the resistance of the Inflator Modules cause voltage drops within the Deployment Loops. The DERM monitors the voltage at "Driver Side Low" terminal "B8" to detect shorts or opens within the Driver Deployment Loop. When the measured voltage is above a specified percentage of "Driver 36 VLR" for 500 milliseconds DTC 23 is set.

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

Failure Conditions: DTC 23 will set when the voltage measured at "Driver Side Low" terminal "B8" is above a specified percentage of "Driver 36 VLR" for 500 milliseconds and DTC 35 is not set.

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

Conditions to Clear: DTC 23 will clear when the voltage measured at "Driver Side Low" terminal "B8" is within a specified percentage of "Driver 36 VLR" for 500 milliseconds.

POSSIBLE CAUSES:
Test Description: Number(S) below refer to circled number(S) on the diagnostic chart.
1. DTCs 23 and 24 together means that there is an open between the Driver Inflator Module Harness Connector and the LH Mid-Rail Discriminating Sensor.
2. This test determines if the malfunction is an open in the LH Mid-Rail Discriminating Sensor between terminal "A" and the splice.
3. This test checks for a open in circuit 348B.

DIAGNOSTIC AIDS:
An open between the driver inflator module harness connector and the discriminating sensor interconnect causes the voltage to increase at "Driver Side Low" due to the loss of a ground path. This also causes the voltage to decrease at "Passenger Side Low" due to decreased current flow through the discriminating sensor network. Refer to Test J (part 5 of 5) to diagnose history DTC 23. DTC 19