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Error code reference

Ariston Cooktop Error Code E.55

FRL cooking zone temperature sensor in open circuit (CO).

Ariston codesAriston cooktop codes

FRL cooking zone temperature sensor in open circuit (CO).

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What E.55 means on a Ariston cooktop

Error code E.55 on an Ariston cooktop indicates that the temperature sensor assigned to the FRL cooking zone has been detected in an open circuit condition. In induction and electric cooktops, each cooking zone is monitored by a dedicated NTC (Negative Temperature Coefficient) or thermocouple-type temperature sensor that continuously reports zone temperature to the control board. An open circuit condition means the electrical path through the sensor circuit is broken, producing no signal or an out-of-range resistance reading that the control board interprets as a fault rather than a valid temperature reading.

The FRL designation identifies the specific cooking zone affected, typically referring to the front-left zone on the cooktop surface. The sensor is connected to the main control board via a wiring harness, and the open circuit fault can originate at several points along that path: the sensor element itself, the connector terminals, the wiring harness, or the control board's sensor input circuit. When the board detects no continuity through the sensor circuit, it disables the affected zone and logs E.55 to prevent uncontrolled heating without temperature feedback.

Common root causes include sensor element failure due to thermal stress or age, corroded or loose connector pins at either the sensor end or the board end, and physical wire damage from heat exposure inside the cooktop cavity. Because the cooktop will not allow the FRL zone to operate while this fault is active, diagnosis should focus on measuring continuity and resistance through the sensor and its wiring before condemning the control board.

Source: manufacturer service documentation.

Common causes of E.55

  1. 01

    Failed temperature sensor

    Part replacement

    The NTC or thermocouple temperature sensor in the FRL zone has failed internally, resulting in an open circuit reading. This can be confirmed by disconnecting the sensor and measuring its resistance with a multimeter; an open circuit (infinite resistance) reading indicates the sensor element has failed.

  2. 02

    Loose or disconnected sensor connector

    Wiring / connection

    The wiring connector between the temperature sensor and the control board harness may have worked loose or partially disconnected due to vibration or heat cycling. Inspect the connector at both the sensor and the board for proper seating and secure engagement.

  3. 03

    Damaged or broken wiring harness

    Part replacement

    The wires running from the FRL zone sensor to the control board can become brittle, cracked, or broken from prolonged heat exposure inside the cooktop cavity. A visual inspection and continuity test of each wire in the harness will identify an open conductor.

  4. 04

    Corroded connector terminals

    Wiring / connection

    Moisture or grease contamination can cause corrosion on the connector pins, increasing resistance to the point where the control board reads the circuit as open. Inspect the terminals for discoloration, pitting, or buildup that would interrupt signal continuity.

  5. 05

    Control board sensor input failure

    Part replacement

    If the sensor and all wiring test correctly, the sensor input circuit on the main control board itself may have failed. This is the least common cause and should only be suspected after all wiring and sensor components have been ruled out.

See the test procedure for each cause

Frequently asked questions about E.55

What does E.55 mean on a Ariston cooktop?
E.55 indicates that the temperature sensor for the FRL (front-left) cooking zone has been detected in an open circuit condition. The control board is receiving no valid signal from that sensor, so it has disabled the affected cooking zone as a safety precaution. The fault points to a broken electrical path somewhere between the sensor element and the control board.
Can I fix E.55 myself, or do I need a technician?
Some causes of E.55, such as a loose connector, can be addressed by a confident DIYer who is comfortable working inside an appliance after disconnecting power. However, testing sensor resistance with a multimeter and tracing wiring faults inside the cooktop requires basic electrical knowledge and proper safety precautions. If the sensor or control board needs replacement, a qualified appliance technician is recommended to ensure correct parts and safe reassembly.
Is it safe to keep using my cooktop with error E.55 active?
The FRL cooking zone affected by E.55 will be disabled and will not operate while the fault is active, so there is no immediate risk from that zone overheating without sensor feedback. However, the remaining zones may still function. It is best to resolve the fault before continued use to avoid any underlying wiring issues that could worsen over time.
Will resetting the cooktop clear the E.55 error?
A power reset by disconnecting the cooktop from mains power for a few minutes may temporarily clear the displayed error, but E.55 will return as soon as the control board performs its sensor check at startup if the underlying fault is still present. The open circuit condition in the sensor wiring or sensor element must be physically repaired for the code to stay cleared.
How much does it cost to repair an E.55 error on an Ariston cooktop?
Repair costs vary depending on what component has failed. A replacement NTC temperature sensor typically falls in the range of $15 to $60 for the part alone. If a technician is needed for diagnosis and installation, labor charges generally add $80 to $150 or more depending on your location. Control board replacement, if required, is the most expensive scenario and can range from $150 to $350 or higher for parts and labor combined.

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