Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) performs tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM monitors the six firing loops to detect leakage currents to ground in the frontal and side air bag inflator module and seat belt pretensioner circuits. The deployment loop resistances are measured to ensure they are within their respective normal resistance ranges. The SDM service wait time is 1 minute. Refer to Air Bag(s) Arming and Disarming.

Conditions for Setting the DTC
The passenger deployment loop resistance is more than 5.0 ohms. The passenger deployment loop consists of the following components:

^ The inflatable restraint IP module.
^ The harness wiring of CKT BA10.
^ The harness wiring of CKT BP10.
^ The connector terminal contact.

The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs continuously during each ignition cycle when the IGNITION 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 and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the DTC to set are no longer existing, the DTC may be cleared using the scan tool. If the resistance in the inflatable restraint IP module circuit is less than 5.0 ohms, a Current DTC 33 will change to a History DTC 33, which may be cleared using the scan tool.

Diagnostic Aids
A poor connection can cause an intermittent condition. Check the following for a poor connection:

^ The inflatable restraint IP module integral 2-way connector.
^ The SDM terminals 3 and 4.
^ The wire to terminal connections in CKT BA10.
^ The wire to terminal connections in CKT BP10.

Inspect CKTs BA10 and BP10 carefully for cutting and/or chafing. The diagnostic table directs the technician to note the entry value of the PASSENGER AIR BAG RES. Comparing the value of the PASSENGER AIR BAG RES. over multiple ignition cycles can be helpful in determining if an intermittent condition exists.

When measurements are requested in this table, use J 39200.

Test Description
The numbers below refer to step numbers on the diagnostic table.

2. This test determines the deployment loop resistance measured by the SDM.
7. This test checks for proper contact or corrosion of the SDM.
12. This test isolates the malfunction to one side of the inflatable restraint IP module yellow 2-way connector. This is done by substituting the known good resistance of the load tool and then, observing if the malfunction is still present.
14. This test determines whether the malfunction is in CKT BA10.
16. This test determines whether the malfunction is in CKT BP10.