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SIR Diagnostic System Check






The diagnostic procedures are designed to find and repair SRS faults. To get the best results, it is important to use the diagnostic charts and follow the sequence listed below:
A. PERFORM THE ""SRS DIAGNOSTIC SYSTEM CHECK." The "SRS Diagnostic System Check" must be the starting point of any SRS diagnostics. The "SRS Diagnostic System Check" checks for proper air bag indicator operation, the ability of the center sensor assembly to communicate through the data link connector (DLC) and whether SRS diagnostic trouble codes (DTCs) exist.
B. REFER TO THE PROPER DIAGNOSTIC CHART AS DIRECTED BY THE "SRS DIAGNOSTIC SYSTEM CHECK." The "SRS Diagnostic System Check" will lead you to the correct chart to diagnose any SRS problems. Bypassing these procedures may result in extended diagnostic time, incorrect diagnosis and incorrect part replacements.
C. REPEAT THE "SRS DIAGNOSTIC SYSTEM CHECK" AFTER ANY REPAIR OR DIAGNOSTIC PROCEDURES HAVE BEEN PERFORMED. Performing the "SRS Diagnostic System Check" after all repair or diagnostic procedures will ensure that the repair has been made correctly and that no other fault conditions exist.

CIRCUIT DESCRIPTION
When the ignition switch is first turned to "ACC" or "ON," system voltage is applied from the CIG & RADIO and the IGN fuses to the center sensor assembly at the "DC-DC Converter" inputs, terminals "B1" and "B3," and from the ECU-B fuse, through the air bag indicator, to the "Diagnosis and Memory Circuits," terminal "B6." The center sensor responds by illuminating the air bag indicator for approximately six seconds while performing tests on the SRS.

NOTES ON SYSTEM CHECK CHART
1. This test checks to see if the air bag indicator circuit is shorted to ground.
2. The air bag indicator should illuminate steady for six seconds and then go off if there are no SRS faults (no DTCs).
3. The air bag indicator will remain illuminated steady if the center sensor assembly has detected a fault and stored a DTC.
4. This test checks for proper operation of "Flash Code" diagnostics.
5. This test checks to see if the center sensor assembly detected a source voltage drop.
6. This test checks to see if the DTC is current or intermittent.
7. Improper operation of the air bag indicator is indicated. This test differentiates a DTC 22 from a fault in the TC CKT.