Before Programming A Control Module

IMPORTANT: Do NOT program an existing control module with the identical software/calibration package. This procedure is not a short cut to correct a driveability condition. This is an ineffective repair. A control module should only be programmed when the following occurs:
^ When a service procedure instructs you to replace the control module. The service part control module does not contain operating software or calibrations.
^ General Motors Corporation releases an updated software/calibration package.

Ensure the following conditions are met before programming a control module:
^ Vehicle system voltage:
- There is no charging system concern. All charging system concerns must be repaired before programming a control module.
- Battery voltage is greater than 12 volts but less than 16 volts. The battery must be charged before programming the control module if the battery voltage is low.
- A battery charger is NOT connected to the 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 the vehicle's battery.
^ Daytime Running Lights (DRL). Applying the parking brake, on most vehicles, disables the DRL system.
^ HVAC systems
^ Cooling System fans, etc.
^ The ignition switch is in the proper position. The scan tool prompts you to turn ON the ignition, with the engine OFF. Do NOT change the position of the ignition switch during the programming procedure, unless instructed to do so.
^ All tool connections are secure:
- RS - 232
- The connection at the DLC is secure.
- Voltage supply circuits
^ DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.
^ If you are performing the pass-through programming procedure using a notebook computer without the power cord, ensure the internal battery is fully charged.