Supplemental Inflatable Restraint (SIR)

Electrical Diagram:

CIRCUIT DESCRIPTION
Code 23 is set when the voltage at the "Sense Low" input, terminal A6," is greater than 78% of "36VLR" output voltage for 500 milliseconds during the "Continuous Monitoring" tests performed by the DERM. The "Continuous Monitoring" tests are performed by the DERM after the initial "Turn ON" tests are completed and are performed every 100 milliseconds while "Ignition 1" voltage is present at the DERM. The "Continuous Monitoring" tests check the continuity of the deployment loop from the "36VLR" output of the DERM through the arming sensor, inflator module, and the discriminating sensors to ground. Code 23 indicates a shorted arming sensor, short to the "36VLR" or an open ground to the deployment loop.

TEST CONDITION(S)
Tested every 100 milliseconds during "Continuous Monitoring"

FAILURE CONDITION(S)
Code 23 will set if the voltage at the "Sense Low" input, terminal "A6," is greater than 78% of "36VLR" output voltage for 500 milliseconds.

ACTION TAKEN
DERM turns "ON" the "INFL REST" warning lamp.

CONDITIONS TO CLEAR
Current Code 23 will clear if the voltage at the "Sense Low" input, terminal "A6," is between 41% and 61% of "36VLR" output voltage for 500 milliseconds (5 consecutive "Continuous Monitoring" cycles) after Code 23 has been set.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines if the fault is in the deployment loop. If voltage at "Sense Low" is greater than 78% of voltage at "36VLR" then the fault is isolated to the deployment loop components and wiring.
2. This test checks for a short from the "36VLR" circuit to the "Force High" circuit.
3. This test checks for a short from the "36VLR" circuit to the high side of the deployment loop.
4. This test determines if the short to "36VLR" circuit is on CKT 347 wiring or the arming sensor.
5. This test checks for a short from the "36VLR" circuit to the "Sense Low" circuit.
6. This test checks for a short from "36VLR" circuit to the low side of the deployment loop.
7. This test checks the integrity of the resistance of the low side of the deployment loop and indirectly determines if the arming sensor diagnostic resistor is within range.
8. This test checks for an open or high resistance condition in the pigtail wiring or internal to the RH sensor between terminals "A and "B".
9. This test checks for an open or high resistance in CKT 348A.
10. This test checks for a high resistance to ground in CKT 1003.