Error Code AL3

If your AEG, Electrolux, Quelle, or Privileg dishwasher displays the error code AL3, it signals a critical failure within the heating system. This code indicates that the appliance is failing to reach the required water temperature within the programmed cycle time, leading to poor cleaning, ineffective sanitization, and often halting the wash program.

Meaning of the AL3 Error Code

The AL3 error code universally points to a heating timeout. The dishwasher’s main control unit (PCB) has initiated the heating process—sending voltage to the element—but the Negative Temperature Coefficient (NTC) sensor has failed to register the necessary temperature rise within the predetermined window (typically 30–60 minutes).

This delay or absence of heating usually signifies a hardware failure related to power delivery or temperature sensing, not a plumbing issue.

Possible Causes for AL3

• Defective Heating Element (Open Circuit): The most common reason. The element may have physically failed, resulting in an open electrical circuit (infinite resistance) and zero heat output.
• Faulty Heating Relay or Triac: Located on the main control board (PCB), this electro-mechanical switch is responsible for routing high-voltage power to the heating element. If the relay fails to close, sticks open, or the soldering joints are cracked, the element receives no power.
• NTC Temperature Sensor Failure: The sensor monitors the water temperature and reports back to the control board. If the sensor is damaged, shorted, or providing drastically inaccurate resistance readings, the control board may fail to enable the heating circuit safely or incorrectly assumes the temperature target has been met.
• Wiring Harness or Connection Issues: Loose, burned, or corroded wiring between the control board, the heating element terminals, or the NTC sensor can interrupt electrical continuity, preventing power delivery or communication.
• Low Water Level: If the pressure switch or flow meter fails, leading to insufficient water in the tub, the heating element may be prevented from turning on as a safety mechanism (dry heating protection).
• Main Control Board (PCB) Failure: Damage or failure within the heater circuit traces on the PCB can cause the AL3 error, even if the external components are functional.

Detailed Troubleshooting Steps

WARNING: Always unplug the dishwasher from the main power supply before accessing internal components. Heating system checks involve high voltage, and professional training is recommended.

1. Unplug and Access the Components:

   • Completely disconnect the appliance from the wall outlet.
   • Tilt the dishwasher back or remove the lower access panel (depending on the model) to gain access to the sump area where the heating element and sensors are located.

2. Test the Heating Element (Resistance Check):

   • Locate the heating element terminals, usually found beneath the dishwasher tub.
   • Set your multimeter to the Ohms (Ω) setting.
   • Place the probes across the two main terminals of the element.
   • A healthy element should read between 15 and 30 Ohms (this varies slightly by model). An infinite reading (OL or 1 on the screen) indicates an open circuit, confirming the element is defective and needs replacement.

3. Verify NTC Temperature Sensor Functionality:

   • Locate the NTC sensor, often attached directly to or adjacent to the heating element or sump.
   • Disconnect the sensor leads and measure its resistance at room temperature.
   • NTC sensors usually read between 10,000 to 15,000 Ohms (10–15 kΩ) at room temperature (about 70°F/21°C). Deviations far outside this range suggest a faulty sensor that needs replacing.

4. Inspect Wiring and Connector Integrity:

   • Visually inspect all wiring leading to and from the heating element and the NTC sensor.
   • Look for signs of corrosion, melted insulation, or loose/burned connectors, particularly where the wiring harness connects to the control board or the element itself. Secure or replace damaged sections.

5. Examine the Main Control Board (Relay Check):

   • If the element and sensor test good, the issue likely resides on the main PCB.
   • If you are comfortable accessing the PCB (often located behind the kickplate or door panel), visually inspect the heating relay. Look for signs of overheating, burn marks, or cracked soldering joints around the relay area. A failed relay necessitates replacing the entire control board (or specialized component-level repair).

6. Test for Sufficient Water Intake:

   • Confirm that the dishwasher is filling to the correct level. If the water level is too low, the pressure switch will prevent the heating element from engaging to avoid burnout. Run a cycle and verify the water height. Clogs in the sump filter can sometimes cause this low-level issue.

When to Call a Pro

While diagnosing the AL3 code using a multimeter is straightforward for the heating element, advanced diagnostics require specialized knowledge:

• If the heating element and NTC sensor test correctly, the problem is likely an intermittent relay or a failed component on the main control board. These repairs involve high voltage components and are best left to a qualified technician.
• If you are uncomfortable working with electricity or dismantling the appliance panels, call a certified appliance repair specialist. They have the proper tools to test energized circuits and efficiently identify complex control board failures.
• If replacement of the main control board is required, a professional can ensure the correct component is installed and properly programmed or configured for your specific model.