Before Programming a Control Module

IMPORTANT: DO NOT program a control module unless you are directed by a service procedure or you are directed by a General Motors Corporation service bulletin. Programming a control module at any other time will not permanently correct a customers concern. Ensure that 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.
- Ensure that the battery voltage is greater than 12 volts but less than 16 volts. If the battery voltage is low, the battery must be charged before programming the control module.
- Ensure that 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.
^ The twilight sentinel
^ The interior lights
^ The daytime running lights (DRL)- Applying the parking brake, on most vehicles, disables the DRL system.
^ The heating, ventilation, and air conditioning (HVAC) systems
^ The engine cooling fans
^ Ensure that 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.
^ Ensure that all tool connections are secure.
- The RS-232
- The connection at the data link connector (DLC)
- The 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.