Hotpoint Dishwasher Error Code AL04

AL04 means the main PCB has detected a fault in the NTC thermistor circuit, either a short circuit or an open circuit caused by a broken cable. The NTC thermistor is the component responsible for monitoring water temperature during the wash cycle. When this circuit is not functioning correctly, the dishwasher stops operating to prevent temperature-related problems. Diagnosis involves checking the thermistor, its wiring, and the PCB connector.

It is not recommended to continue running the dishwasher while AL04 is active. The error means the appliance cannot accurately monitor water temperature, which could result in a wash cycle running at incorrect temperatures. This may leave dishes inadequately sanitised or, in a short-circuit scenario, could cause the heating element to behave unpredictably. The dishwasher should be diagnosed and repaired before further use.

Repair costs depend on which component has failed. If the issue is simply a loose or corroded connector, there may be no parts cost at all. Replacing the NTC thermistor is generally the least expensive parts repair, with thermistors typically costing in the range of $15 to $50 depending on the model. If the main PCB needs replacement, parts alone can range from $80 to $200 or more, with additional labour costs if a technician carries out the work.

Some causes of AL04 are within reach for a confident DIYer. Checking for a loose or disconnected wiring connector and reseating it requires no special tools. Testing the thermistor and cable with a multimeter is also straightforward if you are comfortable working with appliances safely unplugged. However, replacing the thermistor or the main PCB typically requires sourcing the correct parts and some mechanical disassembly of the appliance.

A reset may temporarily clear the displayed error code, but AL04 will return if the underlying fault in the NTC circuit has not been repaired. The main PCB will detect the same short-circuit or open-circuit condition as soon as it runs its diagnostic checks. A reset is useful for confirming whether the fault is intermittent, such as a loose connector, but it is not a permanent fix.