Error E40 in AEG washing machine

Users of AEG washing machines may encounter an unpleasant problem: the machine starts, runs for a few seconds and then turns off, giving code E40. The equipment can be restored to working order only if the problem is fixed. What does error E40 indicate in an AEG washing machine, what actions should be taken to reset it?

Let's decipher and clarify the code

Each washing machine manufacturer sets fault codes and their interpretations. Error E40 displayed automatically AEG, in most cases, indicates a breakdown of the hatch locking device. The control of the AEG washing machine has a diagnostic mode, which will allow you to clarify the causes of the malfunction in the operation of the equipment. If your model does not have a special diagnostic mode, you will have to proceed in a more complicated way:

• simultaneously hold down the two keys located on the right under the number 1;
• At the same time, press the button under number 2. You will have to hold the keys pressed until the entire machine display starts to light up.

If the washing machine has the required software function, instead of these manipulations it will only be enough to switch to diagnostic mode. You can start diagnostics by pressing and holding the two buttons on the right for a couple of seconds.

The diagnostic mode will allow you to clarify the breakdown; instead of error E40, another, more specific code will be displayed on the unit display.

• E41 – will inform you about a leaky door.
• E42 – will tell you about the failure of the hatch locking device.
• E43 - will notify about damage to the triac responsible for the operation of the UBL.
• E44 - indicates that the drum door opening sensor is faulty.
• E45 – will report a break in the electrical circuit between the control board and the UBL.

By clarifying what exactly the problem is, it will be easier to correct the situation. Having some knowledge of the design of automatic washing machines, you can repair the machine yourself. It is better to entrust repair of the control board to specialists.

Checking and replacing UBL

Code E40 does not always indicate a serious equipment malfunction. Perhaps you just didn't close the door tightly. There is no need to immediately start the diagnostic mode; try pressing the hatch with force with your knee. Sometimes this measure really helps, and the machine continues washing as normal.

If this does not help, diagnose the washer using the method described above or check the CMA parts manually. What to do if the reason lies in a faulty lock? To replace the door lock, do the following:

• open the hatch, remove the clamp holding the sealing collar;
• unscrew the bolts securing the UBL;
• remove the lock from the body;
• inspect the device contacts. The third and fourth contacts should be closed, the fourth and fifth should be open;
• install the new lock in its original place, connect the wiring;
• secure the cuff with a clamp;
• run the wash to check the operation of the equipment.

If the machine starts working normally, it means the repair is complete. Replacing the locking device in the vast majority of cases helps to reset error E40.

You can purchase a replacement lock in specialized stores by checking the model number of the AEG washing machine.

Problem with UBL power supply or control board

If the reason for the code being displayed is a faulty lock, you will have to dig deeper. The malfunction may be due to damage to the power supply wiring or the main control board. The lock is connected to the “brain” of the washing machine via electrical wires. If the contact is broken, the “home assistant” informs about this by displaying error E40. You will have to check each wire using a special device - a multimeter.

If the problem is in the triac, located on the control board and responsible for the UBL, a more complex repair awaits. Without some training, experience and knowledge, you will not even be able to find an element on the board. To correct the situation, you will have to resolder the part. For such work it is better to invite a master.

The appearance of the E40 fault code can be caused by damage to any part in the door unlocking and closing system. To determine the breakdown for sure, you will have to check each of the system components.

Thus, error E40 is caused by various damages in the “Control board - Hatch door lock” circuit. You can fix the problem yourself by trying to replace the UBL and diagnosing the integrity of the wiring. If the problem is the failure of the control triac, it is better to call a technician. Repairing the control board yourself can lead to more expensive work if done incorrectly.

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