B0100

CIRCUIT DESCRIPTION

SIR Schematics: Power, Ground, And Sensors:

SIR Schematics: Module Controls:

The Inflatable Restraint Electronic Frontal Sensor (EFS) (also known as Inflatable Restraint Front End Discriminating Sensor) loop is a 2 wire circuit. When the ignition is turned ON, the Inflatable Restraint Sensing And Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM provides input power to the EFS. When input power is first detected, the EFS responds by performing internal diagnostics. Next the EFS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the EFS is powered up. The EFS will continually communicate a status message to the SDM. The SDM can reset the EFS by removing and applying power to it.

CONDITIONS FOR RUNNING THE DTC
^ Ignition 1 Voltage is within the normal operating voltage range.
^ EFS loop is not shorted to voltage.
^ EFS loop is not shorted to ground.

The SDM monitors the EFS loop with the power on.

CONDITIONS FOR SETTING THE DTC
^ The SDM has detected one of the following conditions due to a fault in the EFS interface circuit:
- A valid ID message is not received within 5 seconds of the EFS being powered up.
- Status message is not received.
^ The SDM has failed twice to reset the EFS.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
^ A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
The following can cause an intermittent condition in the EFS circuit:
^ A short to ground or short to voltage in the EFS circuit.
^ High or low resistance.
^ Inspect the EFS signal and ground circuits carefully for cutting and/or chafing

If any of the above conditions are found refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-3:

Steps 4-12:

The number(s) below refer to the step number(s) on the diagnostic table.
6. Test the EFS signal and EFS ground circuits for an open or high resistance.
7. Test between the EFS signal and EFS ground circuits for resistance.
8. Test the EFS signal and EFS ground circuits for a short to voltage.

For a description of the RPO Code(s) shown in this article/images refer to the RPO Code List found at Vehicle/Application ID RPO Codes