Error Code EH4

Error Code EH4: Bistable 0-Watt Relay Malfunction

Error Code: EH4 Appliance Type: Washing Machine Brands: AEG, Electrolux, Quelle-Privileg

Encountering the Error Code EH4 on your AEG, Electrolux, or Quelle-Privileg washing machine indicates a specific, critical electrical fault related to the power management system.

This error points directly to a malfunction involving the bistable “0-Watt relay”.

Understanding the Bistable 0-Watt Relay

The bistable relay is an essential component responsible for managing the main power supply to the machine, ensuring that when the cycle is complete or standby, the machine truly draws zero watts of power (a “0-Watt” state), often required by modern energy efficiency standards. A “bistable” component is one that can maintain two stable states (ON or OFF) without continuous power input to hold the state, relying on a short pulse to switch.

When the control unit detects an anomaly—such as the relay failing to switch correctly, staying stuck in one position, or not providing the necessary switching action for power cutoff—it registers the EH4 error code. This failure prevents the machine from safely entering or exiting a fully powered state as intended by the programmed logic.

Recommended Action

Unfortunately, diagnosis strongly suggests a failure within the main electronic control unit (PCB) itself where this relay is mounted or integrated.

Because the bistable relay is often soldered directly onto the main control board, or its malfunction is indicative of a broader electronic failure within the unit’s central brain:

• Component Replacement: In the vast majority of cases, successfully resolving the EH4 error necessitates the replacement of the entire main control unit.
• Professional Intervention Required: Due to the complexity and the high voltage present within the appliance, attempting self-diagnosis or repair of the main control board is strongly discouraged. This procedure requires specialized electronic knowledge, testing equipment, and safety precautions.

Please contact a qualified repair technician or authorized service center immediately for assistance. They will be equipped to safely confirm the diagnosis and order the correct replacement control unit specific to your model series. Continuing to operate the machine while this error is active could potentially lead to further damage.