Supplemental Inflatable Restraint (SIR)

CIRCUIT DESCRIPTION
The voltage at the "Sense Low" input, Terminal "A6," is within a specific range of "36 VLR" output voltage when "36 VLR" output of the DERM is functional. Should the circuit open between the "36 VLR" output and the arming sensor, "IGN 1" voltage will be supplying the deployment loop. The voltage at the "Sense Low" input Terminal "A6" will decrease due to the lower supply voltage and Code 31 will set after 700 milliseconds (if Code 42 is not set). Code 31 indicates an open in the wiring between the "36 VLR" output of the DERM and the arming sensor.

TEST CONDITIONS
Test every 100 milliseconds during "Continuous Monitoring."

FAILURE CONDITIONS
Code 31 will set if the voltage at the "Sense Low" input, Terminal "A6," is within a specific range of "IGN 1" voltage for 700 milliseconds and Code 42 is not set.

ACTION TAKEN
DERM turns "On" the "Air Bag" telltale lamp.

CONDITIONS TO CLEAR
Cycle Code 31 will clear if the voltage at the "Sense Low" input, Terminal "A6," is within a specific range of "36 VLR" output voltage for 500 milliseconds.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks whether the DERM has set the code falsely.
2. This test checks whether the "36 VLR" is available at the arming sensor.
3. This test determines whether the fault is an open in the arming sensor or a poor connection to the arming sensor.