How to Run Dishwasher Diagnostic Cycle

What Is a Dishwasher Diagnostic Cycle?

A diagnostic cycle — also called a test cycle or service mode — is a built-in self-test that runs the dishwasher through a series of automated checks to identify faults. It tests the water inlet, heating element, drain pump, spray arms, and other components in sequence, and displays error codes for any component that fails the test. Running a diagnostic cycle is the most efficient way to pinpoint a specific fault before ordering parts or calling a technician.

When to Run a Diagnostic Cycle

• The dishwasher is displaying an error code and you want to confirm the fault
• The dishwasher is not performing correctly but no error code is displayed
• You want to verify a repair was successful
• A technician has asked you to run a diagnostic before a service visit

How to Enter Diagnostic Mode — By Brand

The button sequence to enter diagnostic mode varies by brand and model. Always check your specific model’s service manual for the exact sequence. Here are the most common methods:

Bosch Dishwashers

1. Close the dishwasher door
2. Press and hold the Start button for approximately 5 seconds until the display shows a program number or the lights cycle
3. Some models require pressing On/Off then immediately pressing and holding Start
4. The machine will run through its diagnostic sequence automatically

Whirlpool and Maytag Dishwashers

1. Close the door
2. Press the following sequence within 5 seconds: Heated Dry → Normal → Heated Dry → Normal
3. All indicator lights should illuminate to confirm diagnostic mode is active
4. Press Start to begin the test cycle

GE Dishwashers

1. Close the door
2. Press Select Cycle and Start simultaneously and hold for 5 seconds
3. The display will show test mode indicators
4. The machine runs through each component test automatically

Samsung Dishwashers

1. Close the door
2. Press and hold Delay Start and Sanitize simultaneously for 3 seconds
3. The display will show “tE” or similar to indicate test mode
4. Press Start to begin

LG Dishwashers

1. Close the door
2. Press and hold Rinse and Spray simultaneously for 3 seconds
3. The machine enters diagnostic mode and runs automatically

What Happens During the Diagnostic Cycle

The diagnostic cycle runs each component in sequence — typically in this order:

1. Water inlet valve — fills the tub to the correct level
2. Heating element — heats the water to the target temperature
3. Wash pump and spray arms — circulates water through the spray arms
4. Drain pump — drains the water from the tub
5. Any component that fails its test triggers an error code on the display

Reading the Results

• If no error codes appear, all tested components passed
• Note any error codes displayed and look them up in your model’s service manual or online
• The error code identifies the specific component that failed, allowing you to order the correct replacement part

Using a Multimeter Alongside Diagnostics

For electrical component failures identified by the diagnostic cycle, a multimeter confirms whether the component has actually failed before you order a replacement. The Klein Tools Digital Multimeter Kit is a practical tool for testing heating elements, inlet valves, and door switches at home.

Final Tips

• Always check your specific model’s manual for the correct diagnostic sequence — button combinations vary
• Run the diagnostic on an empty dishwasher
• Note all error codes displayed during the test
• A passed diagnostic confirms the machine is functioning correctly — performance issues may be loading or detergent related