B1142

Circuit Description
When you first turn the ignition switch to the ON position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests in order to diagnose critical malfunctions within itself. Next the SDM measures Ignition 1 and the deployment loop voltage in order to ensure that they are within their respective normal voltage ranges. Then the SDM proceeds with the Resistance Measurement test. During one portion of the Resistance Measurement test, the SDM does the following:
^ Grounds the Driver Pretensioner Low terminal 23 through an internal current sink.
^ Connects the Driver Pretensioner High terminal 24 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.
^ Measures the voltage difference between Driver Pretensioner High and Driver Pretensioner Low.
^ Calculates the resistance of the driver pretensioner deployment loop using the measured voltage.

Conditions for Setting the DTC
^ The passenger and driver frontal, and pretensioner deployment loops are not open.
^ The passenger and driver pretensioner deployment loops are not shorted to voltage.
^ The passenger and driver pretensioner deployment loops are not shorted to ground.
^ The driver pretensioner deployment loop resistance is less than 1.3 ohms. The driver pretensioner deployment loop consists of the following components:
- Driver seat belt pretensioner.
- Harness wiring of CKT2118.
- Harness wiring of circuit 2119.
- Connector terminal contact.

The Resistance Measurement test checks for this malfunction. This test only occurs once each ignition cycle when Ignition 1 is within the normal operating voltage range.

Action Taken When the DTC Sets
^ The SDM sets a Diagnostic Trouble Code (DTC).
^ The SDM commands the instrument cluster (IPC) to turn ON the AIR BAG warning lamp.

Conditions for Clearing the MIL/DTC
^ Current DTC
The resistance of the driver pretensioner deployment loop is more than 1.3 ohms and the ignition switch is cycled.
^ History DTC
- You issue a scan tool Clear DTCs command.
- Once 250 malfunction free ignition cycles have occurred.

When you issue a scan tool Clear DTCs command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

Diagnostic Aids
The following can cause an intermittent condition:
^ A short circuit between circuit 2118 and circuit 2116.
^ A short circuit between circuit 2118 and circuit 2117.
^ A short circuit between CKT2118 and CKT2119.
^ A malfunctioning shorting bar on the driver seat belt pretensioner connector.

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 Diagrams. 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 checks for a short from circuit 2116 to CKT2118.
4. This test checks for proper contact or corrosion of the side air bag/pretensioner yellow 6-way connector.
5. This test isolates the malfunction to one side of the side air bag/pretensioner yellow 6-way connector.
6. This test isolates the malfunction to the jumper harness or the pretensioner.
7. This test checks for a short from circuit 2119 to circuit 2118.
9. This test checks for a short from circuit 2118 to circuit 2117.