We have a 2017 Hyundai Tuscon Highlander diesel.
When going at low speed for a length of time the Dash hazzard symbol , auto hold. EPD , anti collision and hill hold light all come on and a loss of power.
When we stop and turn off the engine and restart it is gone.
The dealer is saying no faults are coming up on the computer.
Any advice would be a great help

This is what is on the dash

 

The Automatic Emergency Braking warning is telling us something needs attention.
A dealer should know what to look at, and at least check if the system has a problem.

When you shut the engine down , the computer is allowing a reset. What is required then is to not shut the engine down , but go directly to the dealer and have the system checked for codes in the system. Not always easy to do, but either do that or ,"Let the problem Develop".