When servicing vehicles with the vehicle stability enhancement system (VSES), test drives will be necessary to allow all tests to be run, and all system functions to be enabled and exercised. A test drive may also be required to duplicate specific DTCs covered in this section. The diagnostic system check (including test drive) should be run when vehicle repairs are complete in order to verify the repair. The diagnostic test drive will vary for ABS, TCS, or VSES concerns.

The following is a suggested VSES diagnostic test drive.

1. Read the Diagnostic Aids and the Conditions for Setting the DTC.
2. Turn OFF the ignition.
3. Reconnect any previously disconnected components.
4. Start the engine.
5. Install a scan tool.
6. With the scan tool, observe the Stabilitrak Steering Angle Is Centered parameter in the Delco/Bosch ABS/TCS ICCS2 data list. The scan tool will indicate Yes with the steering wheel centered. Drive the vehicle in a straight line for 45 seconds at 24 Km/h (15 mph) while monitoring the scan tool.
7. Remove the scan tool.

Important: Do not perform any unlawful or unsafe maneuvers.

8. Drive the vehicle under the following conditions for at least 10 minutes.

•	Highway driving.

•	Rough roads.

•	Perform turning maneuvers (curved freeway entrance ramp, parking lot maneuvers) and high steering angles and yaw rates at low speeds.

•	Verify customers concern and duplicate driving conditions.

•	If any DTCs are set, perform the appropriate DTC table.

9. With the engine still running, use the scan tool in order to check for DTCs. If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List .