GE Profile Dishwasher F30 Error Code Fix

What the manual expects you to do for an F30 sensor fault:

• Kill power first. Flip the breaker off or unplug the dishwasher. Do not trust the door switch while you are under the machine.
• Pull the lower kick plate. Remove the screws at the bottom front and take off the metal or plastic panel. Grab the tech sheet if you see it and confirm F30 is a sensor/thermistor issue for your model.
• Do a hard reset once. With the panel off, turn power back on, try a quick cycle. If F30 never comes back, it was a glitch. If it returns, cut power again and keep going.
• Slide the dishwasher out a bit. Loosen the mounting screws at the counter, slide the tub out a few inches so you can see the underside. Do not yank; watch the water line, drain hose, and power cord.
• Find the temperature sensor in the sump. On most GE Profile units it is a small plastic plug with two wires that snaps into the plastic tub bottom, usually near the circulation pump or front corner.
• Inspect the connector and wiring.
  • Unplug the two-wire connector to the sensor.
  • Look for green or white corrosion on the pins.
  • Check for water in the connector or signs of a small leak in that area.
  • Look for chewed, pinched, or burned wires along the harness.
• Dry and reseat if it is just wet or dirty. Blow out moisture, clean contacts with contact cleaner or isopropyl alcohol, click the connector back together firmly, and make sure the harness is not hanging where it will get soaked again.
• Clean the sensor face from inside the tub. Pull the lower rack, find the sensor boss on the floor or lower wall, and if it twist-locks out, remove it. Scrub off hard water scale and food slime with hot water and vinegar, then reinstall it fully seated.
• Meter test if you can.
  • With power off and the sensor unplugged, measure resistance across the two sensor pins at room temperature.
  • A healthy dishwasher thermistor should read in the tens of kilo-ohms range at room temp and drop smoothly as it warms.
  • Reading open (OL) or near zero ohms means the sensor is bad and will trigger F30.
• Replace the sensor if it reads bad or you cannot test it. Order the correct water temperature sensor / thermistor assembly for your exact GE Profile model, snap the old one out, click the new one in, and reconnect the harness.
• Check the harness back to the board. Trace the two sensor wires to the main control board (in the door or behind the toe area, depending on model). Any melted plug, broken insulation, or chewed section needs repair or a new harness.
• Suspect the control board last. If you have a new sensor installed, wiring is clean and solid, and F30 still comes back right away, the main control board is likely misreading the circuit. That means a board replacement or living with a dead dishwasher; run the numbers before you buy that board.
• Reassemble and test. Slide the unit back in without pinching hoses or wires, remount it, reinstall the kick plate, restore power, and run a hot wash. If it completes with no F30, you are done.