Diagnosis
The three dashes is a communication error between the control board and the user interface (the touchpad). It usually means the control board isn't getting a proper signal from the pad, often due to a loose ribbon cable connection.
How to Fix It
You'll need to access the area behind the control panel. 1) Turn off power to the dishwasher at the breaker. 2) The front control panel on this model is usually held by a couple of screws at the top edge inside the door. Open the door and look for them. 3) Carefully lower the panel (it may still be connected by wires). 4) Locate the flat, wide ribbon cable that connects the touchpad to the main control board. Unplug it by pulling straight up on the connector's locking clip, then reseat it firmly. Reassemble and restore power.
If That Didn't Work
The control board itself may have failed. A power cycle can sometimes reset it. Turn off the breaker for 5 full minutes, then turn it back on. If the dashes return, the board likely needs replacement.
Heads Up
Be gentle with the ribbon cable and its connector. The plastic latch is fragile. Don't force it.