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Error code reference

Ariston Dishwasher Error Code AL 12

Hardware version alarm

Ariston codesAriston dishwasher codes

Hardware version alarm - user interface hardware model connected to the Bit100 is not recognized.

First step from the service manual

Verify correct interface card (LED/LCD/Graphics) is connected to the Bit100 timer.

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

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What AL 12 means on a Ariston dishwasher

AL 12 is a hardware version alarm that triggers when the Bit100 timer module cannot recognize the user interface card connected to it. The Bit100 is the main control timer at the core of the dishwasher's operation, and it communicates with a specific type of interface card, which may be an LED, LCD, or graphics-based display panel. When the Bit100 polls the connected interface and receives an unrecognized hardware signature, it throws AL 12 to flag the mismatch before any wash cycle can proceed.

The most common root cause is an incompatible interface card being installed, either due to an incorrect replacement part being fitted during a previous repair, or a factory assembly error. Even within the same product family, different interface card revisions carry different hardware identifiers, and the Bit100 will reject any card whose version ID falls outside its accepted range. This means a physically identical-looking card can still trigger AL 12 if its firmware version or hardware revision does not match what the Bit100 expects.

A secondary cause is a communication fault between the two boards rather than a true hardware mismatch. Damaged connector pins, a loose ribbon cable, or corrosion on the interface connector can corrupt the handshake signal, causing the Bit100 to misread or fail to read the interface card's version data entirely. In this scenario the interface card itself may be the correct type, but the unreliable connection produces the same alarm response.

Source: manufacturer service documentation.

Common causes of AL 12

  1. 01

    Incorrect interface card installed

    Part replacement

    An LED, LCD, or graphics interface card of the wrong hardware version or revision is connected to the Bit100 timer. This is the most likely cause following any prior repair where the interface card was replaced.

  2. 02

    Loose or disconnected interface connector

    Wiring / connection

    The ribbon cable or connector between the interface card and the Bit100 timer is not fully seated, preventing the Bit100 from reading the interface card's hardware version. Check all connectors for secure engagement.

  3. 03

    Corroded or damaged connector pins

    Wiring / connection

    Moisture or wear can corrode the pins on the interface card connector, corrupting the version handshake signal. Inspect the connector contacts closely for oxidation, bent pins, or physical damage.

  4. 04

    Faulty interface card

    Part replacement

    The interface card itself may have failed internally, causing it to transmit an unrecognized or garbled hardware ID to the Bit100. This is suspected when the card type is confirmed correct but the alarm persists after reseating all connections.

  5. 05

    Faulty Bit100 timer module

    Part replacement

    In rarer cases, the Bit100 timer may have a fault that prevents it from correctly reading a valid interface card. This is typically the last component to suspect after the interface card and all connections have been verified.

See the test procedure for each cause

Frequently asked questions about AL 12

What does AL 12 mean on a Ariston dishwasher?
AL 12 is a hardware version alarm indicating that the Bit100 timer module does not recognize the user interface card connected to it. The Bit100 expects a specific LED, LCD, or graphics interface card version, and when the connected card does not match, the alarm is triggered. The dishwasher will not operate until the correct, compatible interface card is confirmed to be properly connected.
How do I fix AL 12 on my Ariston dishwasher?
Start by verifying that the correct interface card type is connected to the Bit100 timer, confirming it matches the LED, LCD, or graphics specification for your model. Next, inspect the connector and ribbon cable between the interface card and the Bit100 for loose connections, corrosion, or damaged pins, and reseat all connectors firmly. If the connection is secure and the card type is correct but the error persists, the interface card or the Bit100 timer may need to be replaced.
Will resetting my Ariston dishwasher clear the AL 12 error?
A simple power reset is unlikely to permanently clear AL 12 because the alarm is tied to a hardware recognition failure that reoccurs every time the Bit100 attempts to communicate with the interface card. The underlying mismatch or connection fault must be corrected first. Once the correct, compatible interface card is properly connected, the alarm should not return.
Is it safe to use my Ariston dishwasher when AL 12 is showing?
The dishwasher will typically prevent normal operation when AL 12 is active, so running a wash cycle is not generally possible while the alarm is present. There is no immediate safety hazard to the home from this error, as it is a communication and compatibility fault rather than a water or electrical danger. However, the appliance should not be used until the fault is resolved to avoid potential secondary issues.
How much does it cost to repair an AL 12 error on an Ariston dishwasher?
If the fix is simply reseating a loose connector, there may be no parts cost at all, though a technician call-out fee would still apply, typically in the range of $75 to $150 depending on your location. Replacing a faulty interface card generally costs between $80 and $200 for the part, plus labor. If the Bit100 timer module itself needs replacement, parts and labor combined could range from $150 to $350 or more, making it worth comparing repair costs against the age and value of the appliance.

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