Supplemental Inflatable Restraint (SIR)

CIRCUIT DESCRIPTION
When you first turn the ignition switch to the RUN position, the inflatable restraint control module performs tests to diagnose critical malfunctions within itself. Next the inflatable restraint control module measures IGNITION 1 voltage to make sure it is within its respective normal voltage range. Then the inflatable restraint control module proceeds with the DEPLOYMENT LOOP CONTINUITY test. During the DEPLOYMENT LOOP CONTINUITY test, the inflatable restraint control module measures the voltage difference between DRIVER SIDE HIGH and DRIVER SIDE LOW.

CONDITIONS FOR SETTING THE DTC
^ The voltage difference between DRIVER SIDE HIGH terminal 2 and DRIVER SIDE LOW terminal 3 is more than or equal to 0.4 volts.
^ The malfunction must be present for at least 500 milliseconds during one of the following tests:
- DEPLOYMENT LOOP CONTINUITY-If the malfunction is detected in this test, the RESISTANCE MEASUREMENT test will not be performed.
- CONTINUOUS MONITORING

ACTION TAKEN WHEN THE DTC SETS
^ The inflatable restraint control module sets a diagnostic trouble code.
^ The inflatable restraint control module turns ON the AIR BAG warning lamp.

CONDITIONS FOR CLEARING THE DTC
^ Current DTC
- The voltage difference between DRIVER SIDE HIGH terminal 2 and DRIVER SIDE LOW terminal 3 is less than 0.4 volts for 500 milliseconds.
^ History DTC
- You issue a scan tool CLEAR CODES command.
- Once 250 malfunction free ignition cycles have occurred.

DIAGNOSTIC AIDS
The following can cause an intermittent condition:
^ A poor connection at the inflatable restraint steering wheel module steering column connector terminals A and B.
^ A poor connection at the upper inflatable restraint steering wheel module coil connector terminals A and B.
^ A poor connection at the inflatable restraint control module terminals 3 and 2.
^ An open in CKT 347.
^ An open in CKT 348.

An intermittent open in the inflatable restraint steering wheel module coil could also set this DTC. To test for a bad Inflatable restraint steering wheel module coil, clear DTCs, then turn the steering wheel back and forth with the ignition switch in the RUN position. If the AIR BAG warning lamp comes ON and DTC 26 has set again it is likely the inflatable restraint steering wheel module coil is malfunctioning.

DTC TABLE TEST DESCRIPTION
Number(s) below refer to step number(s) on the diagnostic table.
2. This test checks for proper contact and/or corrosion of the yellow 2-way connector.
9. This test isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector located near the base of the steering column.
10. This test determines whether the malfunction is the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module.
13. This test checks for proper contact and/or corrosion of the inflatable restraint control module connector.
18. This test determines whether the malfunction is in CKT 347.
20. This test determines whether the malfunction is in CKT 348.