Preliminary Checks

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 1.8L VIBE article.
Ensure the driver understands the A/C compressor operation.
Use a scan tool to ensure the reading of the Vehicle Speed Sensor (VSS) matches the reading of the instrument panel speedometer. Transmission performance can be affected by incorrect VSS readings. If accuracy of the VSS is a concern, see SPEEDOMETER &/OR ODOMETER INACCURATE OR INOPERATIVE in appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.