Ariston Cooktop Error Code E.33

E.33 indicates that the RER (rear right) cooking zone temperature sensor has been detected in an open circuit condition. The control board cannot read a valid signal from that zone's thermistor, so the zone is disabled as a safety precaution. This fault requires physical inspection of the sensor and its wiring to diagnose and resolve.

The affected rear right cooking zone will not operate while E.33 is active, so that specific zone is already disabled by the cooktop's safety system. Other zones may continue to function normally. However, it is not advisable to leave a sensor fault unresolved for extended periods, and you should have the cooktop inspected promptly to confirm no additional wiring or component damage is present.

Repair costs vary depending on what needs to be replaced. A thermistor sensor part alone typically costs in the range of $15 to $60, while a wiring harness may range from $20 to $80. Adding professional labor, total repair costs generally fall between $80 and $200 depending on your location and the technician's rates. A control board replacement, if required, would push costs higher.

Some causes, such as a loose connector, can be addressed by a confident DIYer who is comfortable working inside appliances and taking proper safety precautions by disconnecting power first. However, if the thermistor or wiring harness needs to be replaced, the repair involves disassembling the cooktop and working with internal components, which is generally better suited to a qualified appliance technician. Always disconnect the unit from power before opening it.

Disconnecting power to the cooktop for a few minutes and then restoring it may temporarily clear the fault display, but if the underlying issue with the RER zone sensor or wiring has not been fixed, the error will return as soon as the control board rechecks the sensor circuit. A reset does not repair the open circuit condition.