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Error code reference

AEG Washer Error Code E42

Lid does not unlock at end of program for more than 4 min; triac for door lock defective.

AEG codesAEG washer codes

Lid does not unlock at end of program for more than 4 min; triac for door lock defective.

First step from the service manual

Replace door lock.

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

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What E42 means on a AEG washer

AEG washer error code E42 indicates that the door or lid has failed to unlock within 4 minutes after the wash program has completed. The control board monitors the door lock mechanism and expects to receive a signal confirming the lock has released once the cycle ends. When that release confirmation does not arrive within the 4-minute window, the board logs E42 and keeps the door locked as a safety measure.

The root cause identified for this error is a defective triac within the door lock assembly. The triac is a semiconductor switching component responsible for controlling the electrical signal that actuates the lock solenoid or bimetallic element. When the triac fails, it can no longer properly energize or de-energize the locking mechanism, preventing the door from releasing on command. A shorted triac may keep the lock permanently engaged, while an open triac may prevent it from receiving any signal at all.

Because the triac is integrated into the door lock unit rather than mounted separately on the control board in most configurations, the standard repair approach is to replace the entire door lock assembly. Before replacement, it is worth checking the wiring harness between the control board and the lock for any damaged, corroded, or disconnected connectors, as a wiring fault can produce similar symptoms. However, if wiring checks out, a new door lock assembly is the definitive fix.

Source: manufacturer service documentation.

Common causes of E42

  1. 01

    Defective door lock triac

    Part replacement

    The triac semiconductor inside the door lock assembly has failed, preventing the lock solenoid from receiving the correct signal to release. This is the primary cause listed for E42 and typically requires replacing the door lock unit.

  2. 02

    Failed door lock assembly

    Part replacement

    Beyond the triac specifically, the overall door lock mechanism including the solenoid or bimetallic actuator may have worn out or seized, preventing mechanical release even when signaled. Inspect the lock for visible damage or signs of heat stress.

  3. 03

    Damaged wiring or connector to door lock

    Wiring / connection

    A broken, corroded, or loose connector between the control board and the door lock can interrupt the release signal. Inspect the harness and connectors at both the lock and board ends for continuity and secure seating.

  4. 04

    Control board fault

    Part replacement

    If the main control board is not sending the unlock signal correctly after cycle completion, the door lock will not release. This is less common than a lock failure but should be considered if a new door lock does not resolve the error.

See the test procedure for each cause

Frequently asked questions about E42

What does E42 mean on a AEG washer?
E42 on an AEG washer means the door or lid failed to unlock within 4 minutes after the end of a wash program. The error points specifically to a defective triac inside the door lock assembly. The triac is the semiconductor component that controls the electrical switching of the lock mechanism. Until the fault is resolved, the machine will not allow normal operation.
Can I fix E42 on my AEG washer myself?
A knowledgeable DIYer can address this repair by first checking the wiring harness and connectors between the control board and the door lock for damage or loose connections. If wiring is intact, the next step is replacing the door lock assembly, which is the recommended repair for a defective triac. Always disconnect power before inspecting or replacing any components.
Is it safe to use my AEG washer when it shows E42?
You should not continue using the washer while E42 is active. The door lock fault means the lid may not unlock reliably at the end of a cycle, which creates a practical problem of not being able to access your laundry. Running cycles with a faulty lock can also put additional strain on the control board. Resolve the error before resuming normal use.
Will resetting my AEG washer clear the E42 error?
A power reset may temporarily clear the error code display, but it will not fix the underlying fault. If the triac inside the door lock is defective, the error will return once the machine completes another cycle and the lock again fails to release within 4 minutes. A proper repair requires inspecting and most likely replacing the door lock assembly.
How much does it cost to fix an AEG washer E42 error?
If the repair requires a new door lock assembly and you do the work yourself, parts typically range from around 20 to 60 dollars depending on the specific model. If you hire a technician, total repair costs including labor generally range from 80 to 180 dollars. Costs can be higher if the control board is found to be at fault instead of, or in addition to, the door lock.

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