Before performing this check, there are no DTCs displayed, you have checked the idle air control system, and the ignition timing is correct.

1. Set the parking brake. Block the drive wheels.
2. Connect a scan tool to the DLC with the tool in an open mode.
3. Start the engine. Bring the engine to the normal operating temperature.
4. Check for the correct state of the neutral switch on the scan tool.
5. The idle speed should be 550-650 RPM.
6. If within specifications, the ECM correctly controls the idle speed.
7. If not within specifications, refer to Rough, Unstable, or Incorrect Idle and Stalling and review the information at the beginning of this check.