Ariston Dishwasher Error Code AL 99

AL 99 signals a serial communication failure between the Bit100 timer module and the interface card. These two control boards must exchange data continuously for the dishwasher to operate. When that communication link is broken or disrupted, the machine stops and displays AL 99. The fault is typically caused by a loose cable, an inverted connector, or a problem with the auxiliary starter wash motor.

No, you should not attempt to run the dishwasher while AL 99 is active. The error indicates that critical control components cannot communicate, meaning the machine cannot manage its cycle correctly or safely. Running it in this condition risks improper operation or potential component damage. The fault should be diagnosed and resolved before resuming normal use.

Repair costs vary depending on the cause. If the issue is simply a loose or incorrectly seated connector, a service call to inspect and reseat the wiring could cost between $75 and $150. If the auxiliary starter wash motor requires replacement, parts and labor typically range from $100 to $250. Replacing a failed Bit100 timer or interface card can push the total cost to between $150 and $400 or more, depending on parts availability and local labor rates.

Start by inspecting all cables connected to the serial connector between the Bit100 timer and the interface card, ensuring none are loose, disconnected, or plugged in backwards. Also confirm that the motor and timer connections are secure and correctly oriented. If the wiring is intact, test the auxiliary starter wash motor for proper function. If these steps do not resolve the fault, one of the control boards may need to be replaced by a qualified technician.

A reset may temporarily clear the error code, but if the underlying cause is a physical wiring issue, an inverted connector, or a faulty motor or control board, the fault will return when the machine attempts to operate. A reset is not a repair. The serial communication problem must be identified and corrected to permanently resolve AL 99.