GE Monogram Dishwasher Error 999: Leak Detection... | appliancefaults.com

Technical Background:

The dishwasher's Main Control Unit (MCU) monitors the float switch. When water accumulates in the base pan and raises the float, the switch closes, signaling a leak. The MCU then triggers the 999 error and may initiate a drain cycle. Voltage paths from the float switch connect directly to the MCU input pins.

Symptoms:

The homeowner reports the dishwasher displays a '999' error code. The dishwasher may not start or may stop mid-cycle. There may be visible water on the floor around the dishwasher.

Possible Causes:

Float switch malfunction
Leaking water inlet valve
Damaged or loose drain hose
Circulation pump seal failure
Tub or door seal leak
Clogged or damaged spray arms causing overspray

Solution:

1

Turn off the dishwasher's breaker in the breaker panel.
2

Disconnect the power cord from the outlet or verify 0V AC at the dishwasher's junction box using a multimeter.
3

Access the float switch, usually located in the base of the dishwasher. Inspect for physical damage and free movement. Clean any debris obstructing movement.
4

Use a multimeter to test the float switch continuity in both open and closed positions. Replace if faulty.
5

Inspect the water inlet valve for signs of leakage. Check the valve's solenoid for proper function. Measure the voltage (120V AC) at the valve during the water fill cycle.
6

Carefully examine all hoses and connections for leaks. Tighten clamps with a 5/16-inch nut driver or replace damaged hoses.
7

Check the circulation pump seal for leaks. Replacement of the entire pump assembly may be necessary.

Safety Warning:

Always disconnect power to the dishwasher at the breaker panel before performing any repairs. Lock Out/Tag Out (LOTO) procedures should be followed. High voltage is present in the control circuit.

Prevention:

Regularly clean the dishwasher's filter and spray arms to prevent clogs that can cause leaks. Inspect hoses and connections annually for wear and tear.

Expert Tip:

To enter service mode on some GE Monogram dishwashers, press and hold the 'Start/Reset' and 'Heated Dry' buttons simultaneously for 5 seconds. This allows for diagnostic tests and error code clearing.

Frequently Asked Questions

•Where is the float switch located on a GE Monogram dishwasher?

The float switch is typically located in the base pan of the dishwasher, underneath the wash tub. You'll usually need to remove the lower access panel to see it.

•What voltage should I expect to see at the water inlet valve when it's filling?

You should typically measure approximately 120V AC at the water inlet valve when the dishwasher is actively filling with water.

•How do I clear the error code 999 after fixing the leak?

Clearing the error code typically involves powering the dishwasher off and then back on. Some models might require entering service mode and clearing the code manually through the control panel. Refer to the service manual for your specific model.

GE Monogram Dishwasher Error 999: Leak Detection Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•Where is the float switch located on a GE Monogram dishwasher?

•What voltage should I expect to see at the water inlet valve when it's filling?

•How do I clear the error code 999 after fixing the leak?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: