For 1990-2009 cars only
Important: The following steps must be completed before using the symptom tables:
- Perform the Diagnostic System Check for the subsystem exhibiting symptoms. The subsystem Diagnostic System Check will identify where to begin diagnosis of the data link communications system.
- Review the system operation in order to familiarize yourself with the system functions. Refer to Data Link Communications Description and Operation .
Visual/Physical Inspection
| • | Inspect for aftermarket devices that could affect the operation of the serial data communications system. Refer to Checking Aftermarket Accessories . |
| • | Inspect the easily accessible systems or visible system components for obvious damage or conditions that 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:
