For 1990-2009 cars

Important: The following steps must be completed before using the symptom tables.

1. Before using the symptom diagnostic table, perform the Diagnostic Trouble Code (DTC) List - Vehicle in order to verify the following conditions:

• | There are no DTCs set.

• | The module can communicate via the GM LAN.

2. Review the system operation in order to understand the system functions. Refer to Cruise Control Description and Operation.

### Visual/Physical Inspection

• | Inspect for aftermarket devices which can affect the operation of the Cruise Control System. Refer to Checking Aftermarket Accessories.

• | Inspect the accessible system components or the visible system components for obvious damage or for obvious conditions which can 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 Cruise Control Malfunction in order to diagnose the symptom.