Before Programming the Engine Control Module
NOTE:
DO NOT program a control module unless you are directed by a service procedure or you are directed by a General Motors service bulletin. Programming a control module at any other time may not permanently correct a customers concern.
Ensure the following conditions are met before programming a control module:
- Vehicle system voltage
- There are no charging system malfunctions. All charging system malfunctions must be repaired before programming a control module.
- Battery voltage stays between 12-16 V. If the system voltage is low, charge the battery before performing programming procedure.
- A battery charger may NOT be connected to the vehicle battery while programming. Incorrect system voltage or voltage fluctuations from a battery charger may cause programming error or control module damage.
- Turn OFF or disable any of the following systems that may put a load on the vehicle battery:
- Twilight sentinel
- Interior lights
- Daytime running lamps (DRL). Applying the parking brake, on most vehicles, disables the DRL system. Refer to the Owner's Manual.
- 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 of the following tool connections are secure:
- The connection at the data link connector (DLC)
- The voltage supply circuits
NOTE:
DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming error or control module damage may occur.