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Error code reference

Hotpoint Dishwasher Error Code AL04

Thermistor/NTC circuit not compliant

Hotpoint codesHotpoint dishwasher codes

Thermistor/NTC circuit not compliant - The main PCB has registered a fault in the NTC circuit (short circuit or broken cable detected).

First step from the service manual

Check NTC cables for disconnection; check for NTC short-circuit or open circuit; check for false contact in PCB leads.

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

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What AL04 means on a Hotpoint dishwasher

The AL04 error code on a Hotpoint dishwasher indicates a fault in the NTC (Negative Temperature Coefficient) thermistor circuit. The NTC thermistor is a temperature-sensing resistor that the main PCB uses to monitor wash water temperature throughout the cycle. When the PCB detects either a short circuit or an open circuit (broken cable) in the NTC circuit, it logs AL04 and typically halts the cycle to prevent overheating or incorrect temperature-controlled wash phases.

The NTC thermistor works by changing its resistance in response to temperature changes. A healthy thermistor will show a predictable resistance drop as temperature rises. If the circuit goes open, the PCB reads an unrealistically high resistance value, suggesting the sensor or its wiring has broken continuity. A short circuit causes the opposite: the PCB reads near-zero resistance, mimicking an impossibly high temperature reading. Both conditions are outside the acceptable operating range and trigger AL04.

The most common physical causes include damaged or disconnected wiring between the thermistor and the PCB, corrosion or moisture intrusion at the connector points, a failed thermistor that has drifted out of specification, or a false contact caused by loose pins in the PCB harness. In rarer cases, the main PCB itself may have developed a fault in the circuit that reads the NTC signal, though wiring and the sensor should always be ruled out first before suspecting the board.

Source: manufacturer service documentation.

Common causes of AL04

  1. 01

    Disconnected NTC wiring connector

    Wiring / connection

    The wiring harness connecting the NTC thermistor to the main PCB may have vibrated loose over time. Inspect both ends of the connector for secure seating and signs of pull-out.

  2. 02

    Broken or damaged NTC cable

    Part replacement

    The cable running to the thermistor can develop a break in continuity due to pinching, chafing against components, or corrosion. Use a multimeter to check for continuity along the full cable length.

  3. 03

    Failed NTC thermistor

    Part replacement

    The thermistor itself may have failed in an open-circuit or short-circuit condition, producing a resistance reading outside the expected range. A faulty thermistor will need to be replaced.

  4. 04

    False contact or corroded PCB connector pins

    Wiring / connection

    Moisture or corrosion at the PCB lead connections can cause intermittent or false contact, triggering AL04 even when the thermistor and cable are otherwise intact. Cleaning or reseating the connector may resolve this.

  5. 05

    Main PCB fault in the NTC reading circuit

    Part replacement

    If wiring, connectors, and the thermistor all check out correctly, the PCB itself may have an internal fault in the circuit used to read the NTC signal. PCB replacement is required in this case.

See the test procedure for each cause

Frequently asked questions about AL04

What does AL04 mean on a Hotpoint dishwasher?
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.
Can I fix AL04 on my Hotpoint dishwasher myself?
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.
Is it safe to keep using my dishwasher when AL04 is showing?
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.
Will resetting my Hotpoint dishwasher clear the AL04 error?
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.
How much does it cost to repair an AL04 error on a Hotpoint dishwasher?
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.

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