B1021

When measurements are requested in this table, use J 39200 Digital Multimeter with 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 in Diagrams. When a wire, connector or terminal repair is requested, use J 38125-A Terminal Repair Kit and refer to Wiring Repair. SIR Wiring Repair

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. Next the SDM measures IGNITION 1 and the deployment loop voltages to make sure 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 SIDE LOW terminal 10 through an internal current sink.
^ Connects the DRIVER SIDE HIGH terminal 9 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.
^ Measures the voltage difference between DRIVER SIDE HIGH and DRIVER SIDE LOW.
^ Calculates the resistance of the driver deployment loop using the measured voltage.

CONDITIONS FOR SETTING THE DTC
^ The driver and passenger deployment loops are not open.
^ The driver and passenger deployment loops are not shorted to voltage.
^ The driver deployment loop is not shorted to ground.
^ The driver deployment loop resistance is more than 3.8 ohms. The driver deployment loop consists of the following components:
- Inflatable restraint steering wheel module.
- Inflatable restraint steering wheel module coil.
- Harness wiring of CKT G/R.
- Harness wiring of CKT G.
- 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.
^ The SDM turns ON the AIR BAG warning lamp.

CONDITIONS FOR CLEARING THE DTC
^ Current DTC
The resistance of the driver deployment loop is less than 3.8 ~ and the ignition switch is cycled.

^ History DTC
- You issue a scan tool CLEAR CODES command.
- 250 malfunction free ignition cycles have occurred.

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

DIAGNOSTIC AIDS
A poor connection can cause an intermittent condition. Check the following for a poor connection:
^ The inflatable restraint steering wheel module steering column connector terminals D3 and D4.
^ The upper inflatable restraint steering wheel module coil connector terminals D1 and D2.
^ The SDM terminals 9 and 10.
^ The wire to terminal connections in CKT G/R.
^ The wire to terminal connections in CKT G.

The diagnostic table directs the technician to note the entry value of DRIVER RESISTANCE. Comparing the value of DRIVER RESISTANCE can be helpful in determining if an intermittent condition exists.

DTC TABLE TEST DESCRIPTION
Numbers below refer to step numbers on the diagnostic table.
2. This test determines the deployment loop resistance measured by the inflatable restraint Sensing and Diagnostic Module (SDM).
3. This test checks for proper contact and/or corrosion of the yellow 2-way connector.
10. This test isolates the malfunction to one side of the inflatable restraint steering wheel module yellow 2-way connector located near the base of the steering column.
11. This test determines whether the malfunction is in the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module.
12. This test checks for proper contact and/or corrosion of SDM connector.
14. This test checks for proper contact and/or corrosion of the SDM connector.
19. This test determines whether the malfunction is in CKT G/R.
21. This test determines whether the malfunction is in CKT G.