This is the wiki page for the cvar
The cvar allows you to enter a code that overrides all the items equipped with the item mod. In order to work, cl_itemmod_enabled needs to be enabled.
Any change of the BakkesMod configuration made through the console will be lost when you close Rocket League unless you open and close the GUI once or call the command
(Turn the item mod on with cl_itemmod_enabled)
To load a car loadout from a code, open the console and type
Replace the code with the desired code.
This command does the same as the GUI option of the item mod to load codes.