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Error code reference

Ariston Oven Error Code ER09

Potentiometer 2 disconnected or short circuit

Ariston codesAriston oven codes

Potentiometer 2 disconnected or short circuit - error impossible on Touch control ovens.

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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
  • Verified part numbers when replacement is required
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What ER09 means on a Ariston oven

ER09 on an Ariston oven indicates a fault with Potentiometer 2, specifically a disconnection or short circuit condition detected in that component's circuit. A potentiometer in this context is a variable resistor used to relay the position of a physical control knob to the oven's control board. When the board reads a signal that falls outside the expected resistance range, either because the circuit is open (disconnected) or shorted, it triggers this error to alert the technician to a wiring or component fault.

The error is directly tied to ovens equipped with rotary knob-style controls. The potentiometer translates knob position into a voltage or resistance value that the control board uses to determine the selected function or temperature. A disconnection will typically send no signal or an out-of-range high resistance reading, while a short circuit will produce a near-zero resistance reading. Both conditions are interpreted by the board as a fault state, and normal oven operation is suspended.

Importantly, this error is listed as impossible to occur on Touch control Ariston ovens. Touch control models do not use physical potentiometers for input, so ER09 should never appear on those units under normal circumstances. If ER09 does appear on a Touch control model, this would point strongly to a control board fault or firmware issue rather than a potentiometer problem. On knob-control models, the fault is typically traced to wiring harness damage, a failed potentiometer, or a loose connector at the board or component end.

Source: manufacturer service documentation.

Common causes of ER09

  1. 01

    Loose or disconnected wiring connector

    Wiring / connection

    The connector linking Potentiometer 2 to the control board may have worked loose over time due to vibration or heat cycling. Inspect both the potentiometer end and the board end of the harness for disconnected or partially seated connectors.

  2. 02

    Failed Potentiometer 2

    Part replacement

    The potentiometer itself may have worn out or failed internally, producing either no signal or a shorted reading. Testing the component with a multimeter across its terminals will confirm whether the resistance range is outside the expected specification.

  3. 03

    Damaged wiring harness

    Part replacement

    Wires in the harness running to Potentiometer 2 can become frayed, pinched, or heat-damaged, causing an open or short circuit condition. Visually trace the harness from the potentiometer to the control board and look for any signs of damage.

  4. 04

    Faulty control board

    Part replacement

    If the wiring and potentiometer both test within normal parameters, the control board itself may be misreading the potentiometer signal due to a damaged input circuit. This is a less common cause but should be considered after other components are ruled out.

See the test procedure for each cause

Frequently asked questions about ER09

What does ER09 mean on a Ariston oven?
ER09 indicates that the oven's control system has detected a disconnection or short circuit in the circuit for Potentiometer 2, which is a knob-position sensor used on rotary control models. The oven cannot determine the correct control input and halts normal operation as a result. This error does not apply to Ariston ovens with Touch controls, as those models do not use potentiometers.
Can I fix ER09 on my Ariston oven myself?
If you are comfortable working with appliance wiring, you can inspect the connectors and wiring harness leading to Potentiometer 2 for obvious damage or loose connections. Testing the potentiometer with a multimeter is also within reach for a knowledgeable DIYer. However, if the fault is traced to the control board or requires component replacement, professional repair is recommended to avoid further damage.
Is it safe to use my Ariston oven while ER09 is displayed?
You should not attempt to operate the oven while this error is active. The fault means the control system cannot correctly read the input from Potentiometer 2, which could prevent the oven from responding correctly to your settings. Continuing to use it in this state could lead to unpredictable behavior or further component damage.
Will resetting my Ariston oven clear the ER09 error?
A power reset by switching off the oven at the breaker for a few minutes may temporarily clear the error display, but it will return if the underlying fault in the potentiometer circuit has not been resolved. The root cause, whether a loose connector, damaged wire, or failed component, must be identified and corrected for the error to stay cleared.
How much does it cost to repair an Ariston oven showing ER09?
Repair costs depend on what is causing the fault. If only a connector needs to be reseated, the cost is minimal and may just cover a service call, typically in the range of $75 to $150. Replacing a potentiometer is a relatively affordable parts-and-labor repair, often $100 to $250. If the control board needs replacement, costs can rise to $200 to $450 or more depending on parts availability and labor rates in your area.

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