Nothing, sounds like it is not working,
when it works correctly, if you put it in L when stopped it is in first gear and will stay there until you press the + then it will shift up to how many times you press the +, will shift down on its own as needed but will not go above what you press and it will show on the DIC

so, did the DIC change at all while you were pushing the + button? it will change no matter if you are moving or not

if not, it need to go to the dealer.
some people who tow or crawling or muddding will leave it at a certain number so it does not shift up to a higher gear but still shifts down on it's own

 

No change on DLC, just L. It was stuck in first gear.

 

You aren't the only one, there is a thread or two about the issue

https://www.coloradofans.com/threads/2023-trail-boss-%E2%80%9Climit%E2%80%9D-mode-issue-shift-up-shifted-down.438938/?post_id=5566182#post-5566182

One thing you might try is shifting to L after you are moving along at a decent speed and seeing if the buttons still do nothing. Based on the manual shifting to L will reduce gear by 1 typically if you are moving. But you should then be able to limit them up/down using the buttons. Might be a way to test if your buttons are not working at all.

 

Bill, that worked, but not immediately. First few times the + button caused a downshift. Then everything started working properly and I could use the buttons to up and down shift.

 

That's pretty cool and odd at the same time. Best of luck, I'm not trying it on my truck. Can't be let down if I never touch it hahahahaha

 

I beleive they call that avoidence submission... Reminds me of the guy that never uses the parking brake and 10 years later needs to use it and the cable snaps when he needed it most because it rusted and had dry rot from never using it...

 

Shifting it manually was one of the first things I did when I got the truck and do it frequently in traffic.

 

I drive in the mountains fairly often, and drop it in L while rolling to slow down on downhills, and it's never had a problem. It WILL prevent you from dropping into too low of a gear, and flashes a warning on the dash, so that's cool. Sounds like you have an issue. As mentioned, try dropping into L while you're rolling, and see if that doesn't reset it? It will always select the same or a similar gear to what you were in while in D. I WISH there was a small gear indicator (D1-D8?) while you were in D though like it shows in L, that would be cool.

Best of luck!

 

I shift mine manually all the time. I had it glitch on me twice. Once the +\- buttons just became unresponsive while I had been driving it manually for quite some time. Next trip it worked fine. Another time I swear I pushed the + button and it downshifted.

 

Funny enough the other day leaving the store I must have thought I was in the 4Runner with gated shifter and slapped the truck shifter straight back into L. Tested out the buttons once I realized what I did. They work correctly on my truck.

I'm almost afraid to say anything about how great the truck is and how everything works well. Don't want to jinx it.