B1015

Diagnostic Chart:

Circuit Description
When you first turn the ignition switch to the RUN position, the inflatable restraint Sensing and Diagnostic Module (SDM) perform tests to diagnose critical malfunctions within itself. Next the SDM measures IGNITION POSITIVE VOLTAGE 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 PASSENGER LOW terminal 4 through an internal current sink.
^ Connects the PASSENGER HIGH terminal 1 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.
^ Measures the voltage difference between PASSENGER HIGH and PASSENGER LOW.
^ Calculates the resistance of the passenger 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 passenger deployment loop is not shorted to ground.
^ The passenger deployment loop resistance is more than 3.0 ohms. The passenger deployment loop consists of the following components:

Inflatable restraint I/P module.

- Harness wiring of CKT 1403.
- Harness wiring of CKT 1404.
- Connector terminal contact.

The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs once each ignition cycle when 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 lamp.

Conditions for Clearing the MIL/DTC
^ Current DTC
The resistance of the passenger deployment loop is less than 3.0 ohms and the ignition switch is cycled.
^ History DTC
- You issue a scan tool CLEAR CODES command.

Once 250 malfunction tree 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 I/P module harness connector terminals A and B.
^ The SDM terminals 4 and 1.
^ The wire to terminal connections in CKT 1403.
^ The wire to terminal connections in CKT 1404.

The diagnostic table directs the technician to note the entry value of PASSENGER RESISTANCE. Comparing the value of PASSENGER RESISTANCE over multiple ignition cycles can 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. Intermittent Problems
When a wire, connector or terminal repair is requested, use J 38125-A 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 deployment loop resistance measured by the inflatable restraint Sensing and Diagnostic Module (SDM).
3. This test checks for proper contact or corrosion of the yellow 2-way connector.
10. This test isolates the malfunction to one side of the inflatable restraint IP module yellow 2-way connector.
12. This test checks for proper contact or corrosion of the SDM connector.
17. This test determines whether the malfunction is in CKT 1403.
19. This test determines whether the malfunction is in CKT 1404.