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Code 24 (Chart 1):

DERM Circuit:

DESCRIPTION:

Code 24 is set when the voltage at the Sense Low input (terminal A6) is between 0% and 41% 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 24 will set if the Arming Sensor resistance is too high or open, the Discriminating Sensor resistance is too low or shorted, the "Force Hi", "Sense Hi". "Sense Low" or "Force Low" circuits are shorted to ground or system voltage, the high side of the deployment loop is shorted to the low side.

TEST CONDITION:

Tested every 100 Milliseconds during "Continuous Monitoring".

FAILURE CONDITIONS:

Code 24 will set if the voltage at the Sense Low input (terminal A6) is between 0% and 41% of 36VLR Output Voltage for 500 milliseconds.

CONDITIONS TO CLEAR:

Code 24 will clear if the voltage at the Sense Low input (terminal A6) is between 41% and 61% of 36VLR Output voltage for 500 milliseconds.

ACTION TAKEN:

DERM turns on the "INFLATABLE RESTRAINT" indicator lamp.

NOTES ON FAULT TREE:

1. Checks if fault is in Steering Column.

2. Checks if fault is the diagnostic resistor out of range in the dual sensor.

3. Checks if fault is the diagnostic resistor out of range in the dual sensor.

4. Checks if fault is in Coil Wire or Inflator Module.

5. Checks if fault is a short to voltage on high side of the Steering Column. If no short to voltage is detected, 36VLR voltage will be measured. 36VLR is not system voltage.

6. Checks if fault is a short to voltage in wiring harness or Dual Sensor.