For 1990-2009 cars

Important: Perform the Diagnostic System Check - Cruise Control before using the Symptom Tables in order to verify that all of the following are true:

• | There are no DTCs set.

• | The control module can communicate via the serial data link.

Review the system operation in order to familiarize yourself with the system functions. Refer to Cruise Control Description and Operation .

### Visual/Physical Inspection

• | Inspect for upfitter or aftermarket devices which could affect the operation of the Cruise Control System. 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 one of the following symptom diagnostic procedures in order to diagnose the symptom.

• | For all caterpillar engines refer to caterpillar diagnostic information.

• | Cruise Control Inoperative/Malfunctioning 8.1L.