B1035

Circuit Description
When you first turn the ignition switch to the ON position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM then measures IGNITION 1, 23 VLR and the deployment loop voltages to ensure that the deployment loop voltages are within their respective normal voltage ranges. Next, the SDM proceeds to Continuous Monitoring. The SDM contains a resistor network connected to 5 volts, ground and to the SDM sensor signal terminal 2. The 8.45 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 to appear at the SDM sensor feed input. The SDM monitors this voltage to detect shorts to ground or a closed discriminating sensor.

Conditions for Setting the DTC
^ The SDM is configured for an Inflatable Restraint front end discriminating sensor.
^ The voltage at Sensor Feed terminal 2 is less than 0.5 volts for 500 milliseconds.

The Continuous Monitoring test checks for this DTC. This test occurs when IGNITION 1 is within the normal operating voltage range.

Action Taken When the DTC Sets
^ The SDM sets a diagnostic trouble code.
^ The SDM turns ON the AIR BAG warning lamp.

Conditions for Clearing the DTC
^ Current DTC.
The voltage at Sensor Feed terminal 2 is more than 0.5 volts for 500 milliseconds.
^ History DTC.
- You issue a scan tool CLEAR CODES command.
- 250 ignition cycles occur without a malfunction.

Diagnostic Aids
A short-to-ground in the Inflatable Restraint front end discriminating sensor circuit can cause an intermittent condition. Inspect circuit Gr and the Inflatable Restraint front end discriminating sensor pigtail carefully for cut or chafed wires.

When measurements are requested in this table, use the J 39200 Digital Multimeter with the correct terminal adapter from the J 35616-A Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections. When a wire, connector or terminal repair is requested, use the J 38125-B Terminal Repair Kit.

Test Description

Caution: Be careful when you handle a sensor. Do not strike or jolt a sensor. Before applying power to a sensor:
^ Remove any did, grease, etc. from the mounting surface.
^ Psition the sensor horizontally on the mounting surface.
^ Point the arrow on the sensor toward the front of the vehicle.
^ Tighten all of the sensor fasteners and sensor bracket fasteners to the specified torque value.

Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

The numbers below refer to the step numbers on the diagnostic table.
2. This test checks for a malfunctioning discriminating sensor.
4. This test checks for a short to ground in the GRN wire.