Ariston Dishwasher Error Code AL 04

AL 04 means the control board has detected a fault in the NTC thermistor circuit. The NTC is the water temperature sensor, and the board has found the circuit to be open or shorted for at least 9 seconds. This causes the dishwasher to stop operating until the fault is corrected. The issue can stem from a bad sensor, loose wiring, or in some cases a faulty control board.

No, you should not continue running the dishwasher when AL 04 is active. Without a reliable temperature reading, the machine cannot properly control wash water heat, which can result in poor cleaning performance or potential overheating. The dishwasher typically halts operation when this code appears to prevent further issues.

Repair costs vary depending on the root cause. Replacing an NTC thermistor is typically the least expensive fix, with parts generally ranging from $15 to $50 and labor adding more if a technician is involved. If the control board or timer is at fault, expect total repair costs in the range of $150 to $350 or more depending on parts availability and local labor rates.

Some causes of AL 04 are accessible to a confident DIYer. Start by checking that the NTC sensor connector is firmly seated and that the sensor is properly attached to the tub casing. If the sensor itself has failed, replacing the NTC thermistor is a relatively straightforward repair. However, if the fault traces back to the control board or timer, professional service is recommended.

A reset may temporarily clear the display, but AL 04 will return if the underlying fault in the NTC circuit has not been repaired. Because the fault must persist for 9 seconds before triggering, a reset followed by a new cycle will reproduce the code quickly if the sensor or wiring is still faulty. A proper repair of the thermistor or its connections is needed for the code to stay clear.