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Error code reference

Ariston Oven Error Code ER33

NTC sensor on display board is short or open circuit.

Ariston codesAriston oven codes

NTC sensor on display board is short or open circuit.

First step from the service manual

Replace Display Board.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What ER33 means on a Ariston oven

ER33 is an NTC (Negative Temperature Coefficient) sensor fault specific to the display board on Ariston ovens. Unlike the main oven cavity temperature sensor, this NTC is integrated into or directly connected to the display board itself, where it monitors the ambient or board-level temperature. When the oven's control system detects that this sensor's resistance reading falls outside the expected range, either dropping to near-zero (indicating a short circuit) or rising to an extremely high or infinite value (indicating an open circuit), it triggers ER33 and flags the display board as the source of the fault.

NTC sensors work on the principle that their electrical resistance decreases predictably as temperature increases. A functioning NTC sensor on the display board provides a continuous resistance signal the control system uses to monitor thermal conditions at the board. A short circuit causes resistance to collapse, sending the control system an artificially low or zero reading. An open circuit breaks the signal entirely, sending no reading at all. Both conditions are interpreted as a sensor failure and result in ER33 being displayed.

Because the NTC sensor in this fault is physically located on or directly attached to the display board, the diagnostic approach goes straight to board replacement rather than testing individual wiring runs to a remote sensor. The sensor and board are treated as a single serviceable unit. Attempting to repair a surface-mounted NTC on the display board is generally not practical, making full display board replacement the standard corrective action.

Source: manufacturer service documentation.

Common causes of ER33

  1. 01

    Failed NTC sensor on display board

    Part replacement

    The NTC sensor itself has developed an internal short or open circuit due to age, heat stress, or component failure. This is the most direct cause and is confirmed by the fault code definition itself.

  2. 02

    Damaged display board from heat or moisture

    Part replacement

    Prolonged exposure to high oven temperatures or steam can degrade the display board's components, including the NTC sensor circuit. Visible burn marks, corrosion, or discoloration on the board can indicate this type of damage.

  3. 03

    Loose or corroded board connector

    Wiring / connection

    If the NTC sensor connects to the board via a small plug or solder joint, vibration or corrosion can create an intermittent open circuit. Inspect any accessible connectors at the display board for secure seating before proceeding to full board replacement.

  4. 04

    Wiring fault between sensor and board

    Wiring / connection

    A chafed, pinched, or broken wire in the circuit between the NTC sensor and the display board can produce an open circuit condition that mimics sensor failure. Inspect the wiring harness routing to the display board for visible damage.

See the test procedure for each cause

Frequently asked questions about ER33

What does ER33 mean on a Ariston oven?
ER33 indicates that the NTC temperature sensor located on the display board has been detected as either short circuited or open circuited. The control system cannot get a valid resistance reading from this sensor, so it flags the fault and displays ER33. The display board is the primary component involved in this error.
Can I fix ER33 on my Ariston oven myself?
A knowledgeable DIYer can address ER33 by first checking for any loose connectors or visible wiring damage at the display board. If no wiring fault is found, the fix requires replacing the display board, which involves disconnecting the oven from power and removing the control panel assembly. If you are not comfortable working with oven electronics, a qualified technician should perform the repair.
Is it safe to use my Ariston oven while ER33 is showing?
Operating the oven while ER33 is active is not recommended. The fault indicates the control system is missing sensor data it relies on to monitor conditions at the display board, which could affect how the oven behaves. It is best to stop using the oven until the fault is diagnosed and the display board is inspected or replaced.
Will resetting my Ariston oven clear the ER33 error?
Resetting the oven by cutting power may temporarily clear the display, but ER33 will return if the underlying fault in the NTC sensor or display board has not been corrected. A reset is not a repair. The error will reappear as soon as the control system re-checks the sensor circuit.
How much does it cost to fix ER33 on an Ariston oven?
The cost depends primarily on the price of the replacement display board, which typically falls in the range of $80 to $200 or more depending on the specific model. If a technician performs the repair, add labor costs on top of the part price, which can bring the total to somewhere between $150 and $350 or higher depending on your location and service rates.

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