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Error code reference

AEG Washer Error Code CB

Safety level reached 5 times

AEG codesAEG washer codes

Safety level reached 5 times — pressure switch or valve mechanically defective.

First step from the service manual

Replace pressure switch; check valve for mechanical defect.

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

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What CB means on a AEG washer

Error code CB on an AEG washer indicates that the machine has detected a safety water level condition five consecutive times. The washer's control system monitors the water level through a pressure switch, and when the water reaches a critical safety threshold repeatedly without a normal resolution, the CB code is triggered. This repeated triggering signals that the fault is not random or intermittent, but rather the result of a persistent mechanical failure in the pressure sensing or water inlet system.

The two primary components involved are the pressure switch and the water inlet valve. The pressure switch is responsible for detecting the water level inside the drum and signaling the control board when the water reaches a preset limit. If the pressure switch is mechanically defective, it may fail to accurately report water levels, causing the control board to incorrectly register a safety level condition. Alternatively, a mechanically defective inlet valve that does not close fully can allow water to continuously enter the drum, driving the actual water level to a true safety threshold repeatedly.

Because the code requires five safety-level events before displaying, intermittent or single-occurrence faults are ruled out by the time CB appears. Diagnosis should begin with the pressure switch, inspecting it for mechanical failure and replacing it if defective. The inlet valve should also be examined for any mechanical issue preventing full closure, such as a stuck or warped diaphragm. Both components are relatively accessible and are the defined focus of the diagnostic process for this code.

Source: manufacturer service documentation.

Common causes of CB

  1. 01

    Defective pressure switch

    Part replacement

    A mechanically failed pressure switch can send incorrect water level readings to the control board, causing repeated false safety-level detections. Inspect the switch for damage and test it for proper mechanical response to air pressure.

  2. 02

    Mechanically defective inlet valve

    Part replacement

    An inlet valve with a stuck or warped diaphragm may not close fully after a fill cycle, allowing water to keep entering the drum and triggering a real safety level repeatedly. Check the valve for signs of incomplete closure or continuous water flow when it should be off.

  3. 03

    Blocked or kinked pressure switch hose

    Wiring / connection

    The small rubber hose connecting the drum to the pressure switch can become kinked, clogged, or partially blocked, causing the switch to receive inaccurate pressure signals. Inspect the hose along its entire length for obstructions or deformation.

  4. 04

    Pressure switch hose connection failure

    Wiring / connection

    If the hose has come loose or developed a leak at either the drum port or the pressure switch fitting, the switch cannot accurately detect water levels. Check both connection points for secure attachment and any visible cracking or splits in the hose.

See the test procedure for each cause

Frequently asked questions about CB

What does CB mean on a AEG washer?
The CB error code on an AEG washer means the machine reached its safety water level five separate times, triggering a protective shutdown. This repeated occurrence points to a mechanical fault in either the pressure switch or the water inlet valve. The washer stops operation to prevent overflow or water damage. A component repair or replacement is required to clear this condition.
Will resetting my AEG washer clear the CB error code?
A simple reset is unlikely to permanently clear the CB code because the fault requires five safety-level events before it appears, indicating an underlying mechanical problem. Even if a reset temporarily restores operation, the defective pressure switch or inlet valve will cause the condition to repeat. The root cause must be repaired for the code to stay cleared.
How do I fix the CB error code on my AEG washer?
Start by inspecting and replacing the pressure switch, as this is the primary component identified for this fault. Also check the pressure switch hose for kinks, blockages, or loose connections. If the pressure switch checks out, inspect the water inlet valve for any mechanical defect preventing full closure. Both components are accessible after removing the washer's front or top panel depending on the model.
Is it safe to use my AEG washer while the CB code is active?
No, the washer should not be used while CB is active. The code indicates repeated high water level events caused by a faulty pressure switch or inlet valve. Continuing to run the machine risks water overflow, drum overfilling, or water damage to the appliance and your home. Repair the identified components before resuming use.
How much does it cost to repair a CB error code on an AEG washer?
Repair costs depend on which component is at fault. A replacement pressure switch typically costs between $15 and $50 for the part, while an inlet valve generally runs between $20 and $80. If a technician performs the repair, labor costs will add to the total, bringing the complete repair estimate to a range of roughly $80 to $250 depending on your location and the specific parts needed.

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