Error code · Electrolux Professional · Industrial laundry

Electrolux Washer Extractor Error Code 42: No Parameter Set in MCU

Error code 42 means the motor control (inverter) has no parameter-set value written into it. Switch the machine off for at least 30 seconds and restart. If it returns, the timer software should be updated to the latest version, and if it persists, the motor controller (MCU) is replaced.

Medium · inspection needed

High: the motor control has no settings, so the drum cannot be driven until it is corrected.

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Code: Error code 42, NO PARAMET. SET IN MCU
Maker: Electrolux Professional
Equipment: Industrial laundry
Applies to: Compass Control washer-extractors (CPU board, motor control, DLCU)

What does Electrolux Professional error code 42 mean?

The motor control, also called the MCU or inverter, needs a block of stored settings before it can drive the motor. These parameters tell it how the motor and drum are configured. At power-up the CPU board expects the motor control to hold a valid set. If the parameter-set value is missing, the board shows ERROR 042 / NO PARAMET. SET IN MCU, and the drum cannot be driven. The manual's remedy is simple and in order. First, switch the machine off for at least 30 seconds so the boards restart cleanly, then switch it on again. If the code comes back, the timer software is updated to the latest version, which can write the parameters again. If it still persists after the update, the manual says to replace the motor controller. The message usually appears right at power-up or the first start, before any water.

Affected models and control systems

This applies to the W465H-W4300H, W475S-W4330S and W475N-W4330N washer-extractors, Type W3..., with the Compass Control. The remedy steps are the same for every machine in the range.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

Display shows ERROR 042 / NO PARAMET. SET IN MCU
Machine will not start a program
Message appears at power-up or at first start
No water enters and the drum stays still

Possible causes

Likely causes — what usually sits behind error code 42 on this control. A technician confirms which one it is before any part is replaced.

Short power interruption while the parameters were being written to the motor control
Timer software older than the motor control expects
Motor controller replaced earlier without a matching parameter set loaded

Safe checks before calling for service

✓ What an operator can do

Switch the machine off at the main switch and leave it off for at least 30 seconds.
Switch it on again and start a normal program.
Do not repeat the off and on more than a couple of times.
If the message returns, write down the code and call us. Mention any recent power cut or board replacement.

How a technician diagnoses error code 42

Read the code and confirm the message appears on power-up.
Power the machine off for at least 30 seconds and restart.
Check the timer software version and update it to the latest version.
Confirm that the parameter set is written into the motor control.
Replace the motor controller (MCU) if the code persists after the update.

! Leave this to a technician

Updating the timer software needs the right file, tool and connection to the CPU board.
The motor controller is replaced only after the update fails, and it needs the machine isolated and opened.
Writing parameters with the wrong data can leave the motor driven with wrong settings.

How error code 42 differs from similar codes

Code 42 is a missing parameter set; codes 13 and 45 are communication or tacho problems with parameters present.

Technical reference

Maker documentation: Electrolux Professional owner support
Edition: 438 9228-61/EN, 2011.08.25
Models / control: Compass Control washer-extractors (CPU board, motor control, DLCU)
Section: Troubleshooting, printed p.131 (Error codes)
Checked: October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.

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Error code 42Questions about Electrolux Professional error code 42

Will switching off and on fix it?

Sometimes. The manual starts with at least 30 seconds off, then a restart.

Does the software update matter?

Yes. If the code returns, the manual says to update the timer software to the latest version.

When is the motor controller replaced?

Only if the code persists after the update, per the manual.

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