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 that the following conditions are met before programming a control module:

• Vehicle system voltage:
  • There are no charging system concerns. All charging system concerns must be repaired before programming a control module.
  • The battery voltage is greater than 12 volts but less than 16 volts. The battery must be fully charged before programming the control module.
  • A battery charger is NOT connected to the vehicles 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 vehicles battery. Turn OFF or disable systems such as:
    • Daytime running lights (DRL). Applying the parking brake, on most vehicles, disables the DRL system.
    • Heating, ventilation, and air conditioning (HVAC) systems
    • Engine cooling 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:
  • The RS-232 cable
  • The connection at the DLC
  • The voltage supply circuits
  • The OBPA
• 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 that the internal battery is fully charged.