AEG Washer Error Code E77

E77 on an AEG washer means the control board has detected an open circuit in the NTC thermistor circuit, which is the component responsible for measuring water temperature. The open circuit means the electrical signal from the thermistor is not reaching the board. The washer stops operation because it cannot safely regulate wash temperature without this input.

It is not advisable to continue using the washer when E77 is active. The machine cannot monitor water temperature, which means it could overheat the water or fail to heat it to the correct level. Running cycles in this condition could damage laundry or other internal components.

A power reset may temporarily clear the error code, but it will return as soon as the control board attempts to read the NTC circuit again and finds it open. The underlying cause, whether a faulty ribbon cable, a failed thermistor, or a broken wire, must be physically repaired before the error will resolve permanently.

The first recommended diagnostic step is replacing or reseating the ribbon cable, which is something a confident DIYer with basic electronics knowledge may be able to attempt. However, accessing internal components requires partially disassembling the machine, and working around electrical components carries risk. If you are not comfortable with appliance disassembly, a qualified technician is the safer choice.

Repair costs vary depending on which component has failed. If only the ribbon cable needs replacement, costs are typically in the range of $50 to $150 including parts and labor. If the NTC thermistor needs replacement, expect a similar or slightly lower parts cost, though labor charges still apply. A full diagnostic service call generally runs $75 to $150 before any parts are added.