Operation CHARM: Car repair manuals for everyone.

B1016















Circuit Description
When you first turn the ignition switch to the RUN position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within the SDM. Next the SDM measures IGNITION 1 and the deployment loop voltages 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 performs the following steps:
^ Grounds the PASSENGER SIDE LOW terminal 4 through an internal current sink
^ Connects the PASSENGER SIDE 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 SIDE HIGH and PASSENGER SIDE 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 less than 1.4 ohms. The passenger deployment loop consists of the following components:
- The Inflatable Restraint Instrument Panel (IP) module
- The harness wiring of circuit 1403
- The harness wiring of circuit 1404
- The connector terminal contact
The RESISTANCE MEASUREMENT test inspects 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 passenger deployment loop is more than 1.4 ohm and the ignition switch is cycled.
^ History DTC
- You issue a scan tool CLEAR CODES command.
- After 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
The following may cause an intermittent condition:
^ A short circuit between circuit 1403 and circuit 347
^ A short circuit between circuit 1403 and circuit 348
^ A short circuit between circuit 1403 and circuit 1404
^ A malfunctioning shorting bar on the Inflatable Restraint IP module connector
The diagnostic table directs the technician to note the entry value of PASSENGER RESISTANCE. Comparing the value of PASSENGER RESISTANCE over multiple ignition cycles may be helpful in determining if an intermittent condition exists.

When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616-A Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents. When a wire, connector or terminal repair is requested, use the J 38125-B Terminal Repair kit and refer to Wiring Repairs.

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 SDM.
6. This test isolates the malfunction to one side of the Inflatable Restraint IP module yellow 2-way connector.
7. This test inspects for proper contact or corrosion of the Inflatable Restraint IP module jumper connector.
12. This test determines whether the malfunction is due to the Inflatable Restraint IP module or the module jumper.
15. This test inspects for a short from CKTs 1403 to 1404.
17. This test inspects for a short from CKTs 1403 to 348.