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Error code reference

GE Dishwasher Error Code LOCK LED illuminated (Factory Test)

Turbidity sensor check has failed during factory test mode

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Turbidity sensor check has failed during factory test mode. The control module, wiring, and turbidity sensor are suspect.

First step from the service manual

Press any keypad to stop the control module beeping and move to the next step in factory test mode. Inspect control module, wiring, and turbidity sensor.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What LOCK LED illuminated (Factory Test) means on a GE dishwasher

The LOCK LED illuminated during factory test mode on a GE dishwasher indicates that the turbidity sensor has failed its automated check. Factory test mode runs a series of sequential diagnostic routines to verify the operation of key components before the unit leaves the production line or after a control board replacement. When the turbidity sensor check step fails, the control module signals the fault by illuminating the LOCK LED and generating an audible beeping pattern. Pressing any keypad acknowledges the fault, silences the beeping, and advances the routine to the next diagnostic step.

The turbidity sensor is responsible for measuring water clarity inside the wash tub. It uses an infrared light emitter and receiver to detect suspended food particles and soil load in the water, allowing the control module to adjust cycle length and wash intensity accordingly. A failure during the factory test check means the control module did not receive an expected signal from the sensor within the test parameters. This can stem from a defective sensor, a break or short in the wiring harness connecting the sensor to the control board, or a fault within the control module itself.

Diagnosing this fault requires inspecting the turbidity sensor for physical damage or contamination on its optical window, checking the wiring harness for damaged insulation, loose connectors, or corrosion at the terminals, and evaluating the control module for signs of failure. Because the fault is detected during an automated test cycle, all three components are considered suspect until each is individually verified or eliminated.

Source: manufacturer service documentation.

Common causes of LOCK LED illuminated (Factory Test)

  1. 01

    Faulty turbidity sensor

    Part replacement

    The turbidity sensor itself may be defective, with a failed infrared emitter or receiver preventing it from producing a valid signal during the test. Inspect the sensor's optical window for heavy soiling or physical damage and test the sensor's output signal against expected values.

  2. 02

    Damaged or disconnected wiring harness

    Wiring / connection

    Wiring between the turbidity sensor and the control module can develop breaks, shorts, or loose connector pins, causing signal loss during the diagnostic check. Inspect the full harness run for chafed insulation, corroded terminals, or unseated connectors.

  3. 03

    Contaminated sensor optical window

    Wiring / connection

    Grease, mineral deposits, or food debris coating the sensor's lens can block the infrared beam and cause the sensor to report an invalid reading during testing. Cleaning the optical surface may resolve the fault without replacing the sensor.

  4. 04

    Defective control module

    Part replacement

    If the wiring and sensor both check out correctly, the control module may be failing to properly send test voltage to the sensor circuit or interpret the return signal. A faulty control board can generate this error even when the sensor is functioning normally.

See the test procedure for each cause

Frequently asked questions about LOCK LED illuminated (Factory Test)

What does LOCK LED illuminated (Factory Test) mean on a GE dishwasher?
This indicates that the turbidity sensor failed its check during factory test mode. The turbidity sensor measures water clarity to help the dishwasher adjust its wash cycle. When the test detects no valid signal from the sensor, the control module illuminates the LOCK LED and beeps to flag the fault. The control module, wiring harness, and turbidity sensor are all considered suspect until each is inspected.
Can I fix the LOCK LED factory test error on my GE dishwasher myself?
A knowledgeable DIYer can perform initial checks such as cleaning the turbidity sensor's optical window and inspecting the wiring harness for loose or corroded connectors. If those steps do not resolve the fault, replacing the turbidity sensor or control module typically requires correctly identifying the failed component first. Misdiagnosis can lead to unnecessary part purchases, so methodical testing of each suspect component is important before ordering replacements.
Is it safe to use my GE dishwasher when the LOCK LED factory test error is present?
The LOCK LED fault is triggered during factory test mode, not during a standard wash cycle, so the dishwasher may still operate for normal use. However, a failed turbidity sensor means the appliance cannot accurately monitor water soil levels, which can reduce wash performance. It is best to have the fault diagnosed and repaired before relying on the dishwasher for regular use.
Will resetting my GE dishwasher clear the LOCK LED factory test error?
A power reset will not correct the underlying hardware fault causing the turbidity sensor check to fail. The error will return whenever factory test mode is run again because the control module, wiring, or sensor still has a defect. The fault must be resolved by identifying and repairing or replacing the failed component.
How much does it cost to repair the LOCK LED factory test error on a GE dishwasher?
Repair costs depend on which component has failed. A turbidity sensor replacement typically falls in the range of $30 to $80 for the part alone, while a control module can range from $100 to $250 or more depending on the model. Adding professional labor will increase the total cost. Inspecting the wiring harness first is worthwhile, since a loose connector or damaged wire can sometimes be corrected at little or no parts cost.

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