|     •  | Perform the 
Diagnostic Starting Point 
 before using the Symptom Tables in order to verify that all of
the following are true: | 
 
|        -  | The control module(s) can communicate via the serial data link. | 
 
|     •  | Review the system operation in order to familiarize yourself with
the system functions. Refer to the following: | 
 
Visual/Physical Inspection
|     •  | Inspect for aftermarket devices which could affect the operation
of the power windows, power door locks, or power mirrors. Refer to 
Checking Aftermarket Accessories 
 in Wiring Systems. | 
 
|     •  | 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 
 in Wiring Systems.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order
to diagnose the symptom: