Diagnosis
The "SU" error code on the GE GTW685BSLWS stands for "Suds" or "Suds Lock." This occurs when the machine's pressure sensor detects an abnormal amount of foam in the tub. When excessive suds are present, they create an air pocket or a "cushion" within the pressure tube, which tricks the control board into thinking the water level is inconsistent or that the tub is overflowing, triggering a safety pause to prevent suds from leaking out of the tub and into the internal electronics. This is most commonly caused by using non-HE (High Efficiency) detergent in a machine designed for HE soaps, or by overloading the detergent dosage. If you are using the correct soap, the issue may be caused by "detergent buildup" from previous cycles, where old soap residue has accumulated in the outer tub, causing a sudden spike in foam even with a small amount of new soap. You can confirm this by looking through the glass or opening the lid to see a thick layer of white foam resting on top of the water line.
How to Fix It
To clear the SU error and rescue your load, follow these specific steps:
- Press the Start/Pause button to stop the current cycle. If the machine is unresponsive, press the Power button to turn it off completely.
- Open the lid and inspect the water level. If the foam is higher than 3 inches deep, use a plastic pitcher or a small bucket to manually bail out the soapy water until the foam level is significantly reduced.
- Wait approximately 30 to 60 minutes. This allows the air bubbles trapped in the pressure sensor hose to dissipate naturally, which is necessary for the sensor to reset.
- Close the lid and rotate the cycle selector knob to Rinse & Spin. Do not add any more detergent.
- Press Start. The machine will now attempt to flush the remaining soap from the tub and the pump.
- Once the cycle completes, run one "Clean Washer" cycle (or a hot water cycle with no clothes) to ensure all residual surfactant is removed from the outer tub walls.
If That Didn't Work
- Clear the Pressure Sensor Tube: If the SU code persists without visible suds, the pressure sensor hose (the small clear tube running from the tub to the control board) may be clogged with lint or a "soap plug." Disconnect the power, remove the top panel of the washer, and locate the thin plastic tube. Gently blow air back through the tube toward the tub to clear any obstructions that are mimicking a sudsing condition.
- Perform a Hard Reset: Unplug the washer from the 120V outlet for exactly 10 minutes. This clears the temporary memory of the main control board. While unplugged, press and hold the Start button for 5 seconds to discharge any remaining capacitors. Plug it back in and attempt a Drain & Spin cycle.
- Check the Drain Pump Filter: Debris trapped in the pump can slow down the drainage process, causing soapy water to linger and create foam. Inspect the pump area at the bottom of the machine for any clogs or foreign objects (like coins or socks) that are preventing the water from exiting rapidly.
- Deep Clean with Vinegar: If you suspect detergent buildup, fill the tub with the hottest water setting and add 2 cups of distilled white vinegar. Let it soak for two hours, then run a full cycle. The acid in the vinegar breaks down the alkaline soap scum that causes "phantom suds."
Heads Up
- Detergent Volume: For the GTW685BSLWS, never fill the detergent dispenser to the "Max" line. Use only 1 to 2 tablespoons of HE liquid detergent per load. Over-sudsing is the primary cause of pump failure and board corrosion.
- HE Only: Only use detergents with the "HE" logo. Standard detergents produce 10x more foam, which will inevitably trigger the SU code and can eventually leak into the motor housing.
- Load Balance: Avoid washing very small loads with high amounts of soap. The lack of fabric to absorb the agitation can lead to "whipping" the water into a foam, triggering the sensor.
- Avoid Fabric Softener Overuse: Excessive fabric softener can create a slimy film on the pressure sensor, leading to incorrect water level readings and false SU errors.