DeviceErrors
Error codeE21

LG WM3431HW Error Code E21: Meaning, Fixes & Troubleshooting

LGWasher-DryerWM3431HWUpdated Apr 16, 2026Confidence: medium
Quick fix

LG WM3431HW code E21 usually means the washer-dryer cannot drain correctly. Start with the filter or drain path, check hoses for kinks or blockages, and then retest the appliance.

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SeverityLow
DifficultyEasy
DIY-safe (general)
Time~10 min / ~25 min
Quick fix · Full checks

Summary

LG WM3431HW error code E21 means drain pump error; tub drain taking too long (combo units). This guide explains the likely causes, the safest first checks, and when support or service is the better next step.

Fix it fast

  1. Clean the accessible filter and remove trapped debris from the drain area.
  2. Check the drain hose or outlet path for kinks, crushing, or blockages.
  3. Run a short cycle and confirm the appliance empties fully.

What E21 means

Drain pump error; tub drain taking too long (combo units). On the LG WM3431HW, this code relates to the washer-dryer and should be interpreted together with how the appliance is behaving right now.

Common symptoms

  • The washer-dryer displays E21 instead of normal status information.
  • The current cycle, function, or startup sequence may stop, pause, or behave differently than expected.
  • The same code may return after a reset if the underlying issue is still present.

Most likely causes

  • Drain filter, sump, or outlet path is blocked.
  • Drain hose is kinked, crushed, or blocked, or the pump cannot clear the water properly.

Deeper checks before service

  1. Check whether the fault started after installation or after reconnecting the drain line.
  2. Make sure the waste connection is open and routed correctly.
  3. If the code returns after clearing the drain path, the pump or related control circuit may need service.

Safety warnings

  • Isolate power before reaching into pump or filter areas.

When to contact support

Book service if E21 returns after cleaning the drain path, or if the pump sounds abnormal and the washer-dryer still cannot empty correctly.

FAQ

Can E21 clear after a reset?
Sometimes a temporary glitch clears after one full reset, but a repeated return usually means the same underlying issue is still there.
Should I keep using the appliance if it works again briefly?
Only if the code stays away and the appliance behaves normally. If the same code comes back, stop and move to service or more targeted diagnosis.

What to record before LG support or repair

  1. Photograph the full display and the product label or rating plate.
    ExpectedYou can confirm the exact model and avoid support or parts quotes against the wrong product variant.
  2. Note whether the appliance was idle, starting up, heating, filling, draining, cooling, or finishing a cycle when the code appeared.
    ExpectedYou have the timing detail that usually matters most in fault triage.
  3. Write down any recent changes such as a power interruption, filter clean, leak, unusual noise, smell, moved installation, or repeated manual reset attempts.
    ExpectedSupport can separate a recent event from a longer-running repeat fault faster.

Next actions if E21 keeps coming back

If E21 returns after one clean restart and the user-accessible checks above, treat that as a repeat fault. The safest next move is to compare the model hub, confirm the official manual-safe checks for this device, and then escalate with a clear symptom record instead of opening panels or replacing parts blind.

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