GE Dishwasher Error Code 999: Sump Gasket Replacement... | appliancefaults.com

Technical Background:

The MCU (Main Control Unit) monitors water levels and pump performance. Error 999 often indicates an issue with water pressure or flow, frequently triggered by a leak in the sump area affecting pressure sensors. The MCU interprets abnormal sensor readings as a pump or water supply problem.

Symptoms:

The homeowner observes water pooling under the dishwasher, particularly during or after a wash cycle. The dishwasher displays error code 999. The unit may also be louder than usual, suggesting the pump is working harder due to low water pressure.

Possible Causes:

Worn or cracked sump gasket.
Improper sump system.
Debris trapped between the sump and tub.
Warped or damaged sump housing.
Over-tightened sump bolts (leading to gasket damage).
Blocked or restricted water inlet valve.

Solution:

1

Disconnect power to the dishwasher at the breaker panel. Verify 0V AC at the dishwasher's power connection using a multimeter.
2

Remove the lower access panel (kick plate) using a 1/4-inch nut driver.
3

Disconnect the water supply line from the inlet valve. Have a bucket ready to catch any remaining water.
4

Disconnect the drain line from the sink drain or garbage disposal.
5

Carefully slide the dishwasher out from under the countertop.
6

Disconnect all electrical connections to the sump assembly. Take pictures before disconnecting.
7

Remove the sump assembly. Inspect the gasket for cracks or damage. Replace the gasket with a new GE-approved gasket.
8

Reinstall the sump assembly, ensuring the gasket is properly seated. Tighten the bolts to the manufacturer's recommended torque specification (typically around 8-10 inch-pounds). Do not overtighten.
9

Reconnect all electrical connections, the water supply line, and the drain line.
10

Slide the dishwasher back into place and secure it.
11

Reinstall the lower access panel.
12

Restore power to the dishwasher at the breaker panel.
13

Run a test cycle to check for leaks.

Safety Warning:

Always disconnect power at the breaker panel before working on any appliance. Verify the absence of voltage with a multimeter. Lock Out/Tag Out (LOTO) procedures should be followed to prevent accidental re-energizing of the circuit.

Prevention:

Regularly inspect the sump area for leaks. Avoid overloading the dishwasher with excessive detergent, which can accelerate gasket degradation. Use a dishwasher cleaner monthly.

Expert Tip:

After replacing the sump gasket, enter the dishwasher's service mode (typically holding down specific buttons for a few seconds - consult the service manual for your exact model) and run a diagnostic cycle to clear the error code and ensure proper operation.

Frequently Asked Questions

•What is the proper torque specification for the sump bolts?

The torque specification is typically around 8-10 inch-pounds. Refer to the service manual for your specific model.

•How do I enter service mode on my GE dishwasher?

Service mode entry varies by model. Consult the service manual or search online using your specific model number and 'service mode'.

•What should I do if the error code returns after replacing the sump gasket?

Check for other potential leaks in the sump area, inspect the pump for damage or obstructions, and verify proper operation of the water inlet valve. Also, ensure the pressure sensor is functioning correctly.

GE Dishwasher Error Code 999: Sump Gasket Replacement Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the proper torque specification for the sump bolts?

•How do I enter service mode on my GE dishwasher?

•What should I do if the error code returns after replacing the sump gasket?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: