Before Programming Procedure

WARNING: This page is about a different car, the 2001 GMC Safari and 2001 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.

Ensure following conditions are met before programming a control module:

Vehicle system voltage, there are no charging system concerns.
Battery voltage is greater than 12 volts but less than 16 volts. Battery must be charged before programming control module if battery voltage is low.
Ensure a battery charger is not connected to vehicle's battery. Incorrect system voltage or voltage fluctuations from a battery charger, may cause programming failure or control module damage.
Turn off or disable any system that may put a load on vehicle's battery. Twilight sentinel, Interior lights, Daytime running lights (DRL), disables DRL system, by applying parking brake. Turn off HVAC systems and blower motors. Engine cooling fans etc.
Follow programming procedure. Ensure ignition switch is in proper position. Scan tool prompts you to Turn ignition switch to RUN position with engine off. DO NOT change position of ignition switch during programming procedure, unless instructed to do so.
Ensure all tool harness connections are secure. DO NOT disturb tool harnesses while programming. If an interruption occurs during programming procedure, programming failure or control module damage may occur.