Circuit Description
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 Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Test the EFS signal and EFS ground circuits for an open or high resistance.
-
Test between the EFS signal and EFS ground circuits for resistance.
-
Test the EFS signal and EFS ground circuits for a short to voltage.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: SIR Schematics | ||||
1 | Did you perform A Diagnostic System Check - SIR? | -- | Go to Step 2 | |
2 |
Does connector exhibits any signs of damage or corrosion? | -- | Go to Step 3 | Go to Step 4 |
3 |
Did you complete the repair? | -- | Go to Step 12 | -- |
4 |
Does the scan tool indicate that this DTC B0100 is current? | -- | Go to Step 5 | Go to Diagnostic Aids |
5 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 | |
Test the resistance between the EFS signal circuit and the EFS ground circuit on the SDM connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does the resistance measure less than the specified value? | OL | Go to Step 10 | Go to Step 8 | |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | |
9 | Replace the EFS, also known as inflatable restraint front end discriminating sensor. Refer to Inflatable Restraint Front End Discriminating Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 11 | System OK |
11 |
Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
