Diagnosis
F9 E1 is a water heating fault. The control board detected the water did not reach the target temperature within the expected time.
How to Fix It
Check the inlet water temperature. The incoming water must be at least 120°F for proper operation. Increase your home's water heater setting. Run a hot water tap near the dishwasher for one minute before starting a cycle.
If That Didn't Work
The heating element may be scaled or failed. You need to test the element for continuity. Disconnect power. Access the element through the lower front panel. Disconnect the wires and measure resistance across the terminals; it should read 10-30 ohms.
Heads Up
Running cycles with cold inlet water is the primary cause of this code. It stresses the heater and can lead to premature failure.