B1025

Circuit Description

When you first turn the ignition switch to the RUN position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests in order to diagnose critical malfunctions within the module. Upon passing these tests the ignition positive voltage, the 23 Volt Loop Reserve (23 VLR) and the deployment loop voltages are measured in order to ensure that the voltages are within the respective normal voltage ranges. The SDM monitors the voltages at the DRIVER LOW terminal 3 and the PASSENGER LOW terminal 4 in order to detect shorts to B+ in the inflator module circuits.

Conditions for Setting the DTC

^ The voltage at the PASSENGER LOW terminal 4 is less than 4.8 volts.

^ The voltage at the DRIVER LOW terminal 3 is more than 4.8 volts for 500 milliseconds.

The continuous monitoring test inspects for this DTC. This test occurs when the ignition positive voltage 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 Indicator.

Conditions for Clearing the MIL/DTC

^ Current DTC

The voltage at DRIVER LOW terminal 3 is less than 4.8 volts for 500 milliseconds.

^ History DTC

- You issue a scan tool CLEAR CODES command.

- 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

A short to B+ in the Inflatable Restraint Steering Wheel Module circuit may cause an intermittent condition. Carefully inspect circuit 347 and circuit 348 for cut or chafed wires. The diagnostic table directs the technician in order to note the entry value of the DRIVER SENSELO. Comparing the value of the DRIVER SENSELO may be helpful in determining if an intermittent condition exists.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from 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 J 38125-B Terminal Repair kit and refer to Wiring Repair.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

2. This test determines the driver low voltage measured by the Inflatable Restraint Sensing and Diagnostic Module (SDM).

3. This test isolates the malfunction to one side of the Inflatable Restraint Steering Wheel Module Coil yellow 2-way connector.

4. This test determines whether the malfunction is due to the Inflatable Restraint Steering Wheel Module or the module coil.

7. This test determines whether the malfunction is in circuit 347.

9. This test determines whether the malfunction is in circuit 348.