Supplemental Inflatable Restraint (SIR)

Code 41:

DERM Circuit Detail:

DESCRIPTION:

The DERM measures the deployment loop energy reserve voltage (36VLR) and checks that it has reached at least 28.4 volts within 7 seconds "IGNITION 1" voltage is applied to the DERM. Code 41 indicates an internal fault in the DERM or a resistive short to ground in the 36VLR circuit to the Arming Sensor.

TEST CONDITION:

Tested once during each ignition cycle at "Turn-on".

FAILURE CONDITIONS:

Code 41 will set if the 36VLR output of the DERM has not reached at least 28.4 volts within 7 seconds after "IGNITION 1" voltage is applied to the DERM.

CONDITIONS TO CLEAR:

Current Code 41 will be cleared each time the Ignition Switch is turned OFF.

ACTION TAKEN:

DERM turns on the "INFLATABLE RESTRAINT" indicator lamp.

NOTES ON FAULT TREE:

1. Checks for a resistive short to ground in the 36VLR circuit between the DERM and the Dual Sensor.

2. Checks for a short to system voltage on 36VLR circuit.

3. Checks for a resistive short to ground within the Dual Sensor.

4. Checks for shorted diode in Dual Sensor. If the resistance valve of the 3.48k ohm resistor can be read on a meter, this indicates a shorted diode.