Supplemental Inflatable Restraint (SIR)

Code 23:

DERM Circuit Detail:

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, shorted harness, or open ground path on both Discriminating Sensors.

TEST CONDITION:

Tested every 100 milliseconds during "Continuous Monitoring".

FAILURE CONDITIONS:

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.

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.

ACTION TAKEN:

DERM turns on the "INFLATABLE RESTRAINT" indicator lamp.

NOTES ON FAULT TREE:


1. Checks circuit 348A for an open circuit.

2. Checks the 36VLR circuit for a short to the low side of the steering column (CKT 349).

3. Checks the 36VLR circuit for a short to the high side of the steering column (CKT 347A).