SRS Diagnostic System Check

The diagnostic procedures used in this section are designed to find and repair SRS malfunctions. To get the best results, it is important to use the diagnostic charts and follow the sequence listed:

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" warning lamp operation, the ability of the SDM to communicate through the "Serial Data" line and whether SRS diagnostic trouble codes 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 malfunctions. Bypassing these procedures may result in extended diagnostic time, incorrect diagnosis and incorrect parts replacement.

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 malfunctions exist

Circuit Description
When the ignition switch is first turned "ON", "ignition 1" voltage is applied from the "SRS-1" fuse to the SDM at the "ignition 1" input terminals "12". The SDM responds by flashing the "AIR BAG" warning lamp seven times while performing tests on the SRS.

Notes On System Check Chart:
Number(s) below refer to step number(s) on the "SRS Diagnostic System Check" chart.

1. The "AIR BAG" warning lamp should flash seven times after ignition is first turned "ON."
2. After the "AIR BAG" warning lamp flashes seven times, it should turn "OFF."
3. Improper operation of the "AIR BAG" warning lamp is indicated. This test differentiates a warning lamp stays "ON" condition from a warning lamp does not come "ON" condition.
4. This test checks for the proper operation of the "Serial Data" line. This test will also determine whether history diagnostic trouble codes are stored and, if so, identify them.
5. This test checks for proper operation of the "Serial Data" line. This test will also identify the stored diagnostic trouble codes and whether they are current or history.

Step 1 - 4:

Step 5:

Diagnostic Aids
The order in which diagnostic trouble codes are diagnosed is very important. Failure to diagnose the diagnostic trouble codes in the order specified may result in extended diagnostic time, incorrect diagnosis and incorrect parts Replacement.