The only code I am able to find that may work is 833. To program a remote into AUX mode, just hold the AUX button until all the lights come on. Let go, and press 2 then 833 and press #. See if anything works. If not, let me know and I will try some other steps. What model of remote do you have?
There are two options to try based on that remote. The first one would be a power scan which lets you scan each individual code until you find a working one. The other option would be to utilize the learning feature on the remote. I will list the steps to do a power scan here, and you can check the link below for the steps to use the learning feature!
With the soundbar on, press and hold the AUX mode button (about six seconds) on the top of the remote until all mode buttons light up, then release. Press 2, then press STAR (*)
Press the Up arrow button once per second while pointing the remote at the equipment. If the code for it comes up, the equipment power off.
When it does, press the POUND (#) button. If the code entered is valid for the remote, the mode light will flash three times. To verify the code works try several different functions for that equipment.
If both of these options don't work, then it is possible our remote may not be able to work that equipment.