GE Dishwasher Error 999: High Humidity & Leak Protect... | appliancefaults.com

Technical Background:

The GE dishwasher's Main Control Unit (MCU) monitors the Leak Protect sensor. The sensor typically works by detecting the presence of water, completing a circuit and signaling the MCU. The MCU then triggers the error code 999 and potentially shuts down the dishwasher to prevent further water damage. A small voltage, typically 5V DC, runs through this circuit. Higher than normal ambient humidity can sometimes cause condensation on the sensor or affect the sensor's resistance, triggering a false positive.

Symptoms:

US homeowners report that their GE dishwasher displays error code 999, especially during or after periods of high humidity, like after a shower or when boiling water. Some users mention the dishwasher otherwise functions normally until the error appears. Resetting the dishwasher may temporarily clear the code, but it reappears within a short time.

Possible Causes:

High humidity levels in the kitchen
Condensation buildup on the Leak Protect sensor
Faulty Leak Protect sensor
Wiring issues in the sensor circuit
MCU malfunction (rare)
Drain issues causing residual water near the sensor

Solution:

1

Disconnect power to the dishwasher at the breaker panel. Verify with a multimeter at the dishwasher's power connection (should read 0V AC).
2

Locate the Leak Protect sensor at the base of the dishwasher tub. Usually accessible from the front lower panel, secured with a 1/4-inch nut driver.
3

Inspect the sensor and surrounding area for moisture or debris. Clean with a dry cloth. Use a small brush to remove any mineral deposits.
4

Check the sensor wiring harness for damage or loose connections. Use a multimeter set to ohms to test the sensor's resistance, compare to known good values if available. Inspect the connector pins for corrosion. Apply dielectric grease to connector.
5

If the wiring and sensor appear okay, replace the Leak Protect sensor. Order the correct replacement part number from a reputable supplier.
6

Clear any clogs in the dishwasher drain system. Check the drain hose for kinks or obstructions.
7

Restore power at the breaker panel and test the dishwasher by running a short cycle. Monitor for error code 999 reappearance.

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. Dishwashers operate on 120V AC; improper handling can cause serious injury or death.

Prevention:

Ensure proper ventilation in the kitchen to minimize humidity. Regularly clean the dishwasher and check for leaks. Run a vinegar cycle monthly to prevent buildup.

Expert Tip:

To enter service mode on some GE dishwashers, press and hold the 'Start' and 'Heated Dry' buttons simultaneously for 5 seconds. This will allow you to run diagnostic cycles and view error history.

Frequently Asked Questions

•What is the typical resistance range I should see when testing the Leak Protect sensor with a multimeter?

The resistance should typically be very high (near infinite) in a dry state and drop significantly (close to 0 ohms) when wet. However, consult the service manual for your specific model for exact values.

•If the sensor is new and the error persists, what else could cause a false reading?

Check the wiring harness for shorts to ground or other wires. Also, ensure the drain hose is properly routed and not causing water to back up near the sensor.

•Could a faulty door seal contribute to the error 999?

Yes, a leaking door seal can cause water to accumulate in the base of the dishwasher, potentially triggering the Leak Protect sensor. Inspect the door seal for damage or wear and replace if necessary.

GE Dishwasher Error 999: High Humidity & Leak Protect Sensor Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance range I should see when testing the Leak Protect sensor with a multimeter?

•If the sensor is new and the error persists, what else could cause a false reading?

•Could a faulty door seal contribute to the error 999?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: