Important: Complete the following steps before using the symptom tables:
- Perform 
Diagnostic System Check - Vehicle before using the symptom tables in order to verify that all of the following are true:
 
| •  | The inflatable restraint sensing and diagnostic module (SDM) can communicate via the serial data link. | 
 
- Review the SIR system description and operation in order to familiarize yourself with the system functions. Refer to 
SIR System Description and Operation.
 
Visual/Physical Inspection
|     •  | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom. | 
 
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to 
Testing for Intermittent Conditions and Poor Connections.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: