B1136

CIRCUIT DESCRIPTION
When you first turn ON the ignition, the Inflatable Restraint Sensing And Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM proceeds to continuous monitoring. The SDM contains a resistor network connected to 5 volts, ground, and to the SDM front end sensor feed. The 1.0 K ohm resistor in the inflatable restraint front end discriminating sensor parallel to the normally open switch provides a parallel path to ground. This causes a specified percentage of voltage in order to appear at the SDM front end sensor feed input. The SDM monitors this voltage to detect a short to voltage or an open discriminating sensor.

CONDITIONS FOR RUNNING THE DTC
^ The SDM is configured for an inflatable restraint front end discriminating sensor.
^ Ignition 1 Voltage is within the normal operating voltage range.
^ Front end discriminating sensor signal circuit is not shorted to voltage.

CONDITIONS FOR SETTING THE DTC
Front end discriminating sensor signal circuit is more than 3.4 volts for 500 milliseconds.

ACTION TAKEN WHEN THE DTC SETS
The SDM commands the AIR BAG warning indicator ON 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:
^ A short to voltage in the front end discriminating sensor signal circuit.
^ Cutting or chafing of front end discriminating sensor signal and/or ground circuit.

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Diagnostic Aids for Circuit Testing and Wiring Repair procedures.

TEST DESCRIPTION

Steps 1-3:

Steps 4-11:

The numbers below refer to the step numbers on the diagnostic table:
4. Test the resistance of discriminating sensor circuits.