Constant Power for Reprogramming
Whether you are reprogramming on board or off board, you must be sure that the power supplied to the module does not drop below proper voltage. Some reprogramming operations with the key-on will turn on cooling fans, fuel pumps, and other components that will cause the battery to drain faster than normal.
Instead of pulling fuses to prevent the battery drain, it is easier and more practical to have the vehicle connected to a charger or jump pack. During reprogramming there is a risk of having the operation fail if voltage falls below the proper operating range. Sometimes a failed operation can be recovered, but there is a chance that failed reprogramming could ruin the control module. To mitigate this risk, put a high-quality AE Tools programming power supply on the vehicle if you are reprogramming.