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Error code reference

Ariston Oven Error Code ER70

I2C communication fault

Ariston codesAriston oven codes

I2C communication fault - power supply board communication defective.

First step from the service manual

Replace the power supply board.

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

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What ER70 means on a Ariston oven

The ER70 error code on an Ariston oven indicates a fault in the I2C communication bus involving the power supply board. I2C (Inter-Integrated Circuit) is a serial communication protocol used internally to allow the oven's control boards to exchange data. When the power supply board fails to communicate correctly over this bus, the main control board detects the breakdown and triggers the ER70 fault, halting normal operation to prevent unsafe conditions.

The power supply board is responsible for converting and distributing electrical power to the oven's control circuitry while also participating in the I2C data exchange. A defective power supply board can disrupt this communication through internal component failure, corrupted signal output, or a loss of the voltage reference required to sustain the I2C bus logic levels. Wiring harness issues between the power supply board and the main control board can also mimic this fault by introducing signal interruption or data corruption on the communication lines.

Because the diagnostic guidance points directly to replacing the power supply board as the first step, internal board failure is considered the primary cause rather than a recoverable software glitch. Technicians should also inspect the ribbon cables and wire connectors linking the power supply board to the control board for damage, corrosion, or poor seating before condemning the board entirely, as a loose connector can produce identical communication faults.

Source: manufacturer service documentation.

Common causes of ER70

  1. 01

    Failed power supply board

    Part replacement

    Internal component failure on the power supply board disrupts the I2C data bus, preventing communication with the main control board. This is the most likely cause and the first component targeted for replacement.

  2. 02

    Loose or damaged wiring harness connector

    Wiring / connection

    A connector between the power supply board and the main control board that is corroded, unseated, or damaged can interrupt I2C signals and trigger ER70. Inspect all relevant connectors for secure seating and visible damage.

  3. 03

    Damaged ribbon cable or communication wiring

    Part replacement

    Physical damage such as pinching, fraying, or heat exposure on the wiring between the two boards can corrupt the I2C signal. A careful visual inspection of the cable routing should be performed.

  4. 04

    Main control board fault

    Part replacement

    If the power supply board tests correctly and all wiring is intact, the main control board may have failed in a way that prevents it from receiving or interpreting the I2C signal. This is a secondary possibility after the power supply board is ruled out.

See the test procedure for each cause

Frequently asked questions about ER70

What does ER70 mean on a Ariston oven?
ER70 on an Ariston oven indicates an I2C communication fault involving the power supply board. The I2C bus is an internal serial protocol that allows the oven's circuit boards to exchange data, and ER70 means this communication has broken down. The most common cause is a defective power supply board, which requires replacement to resolve the fault.
Can I fix the ER70 error on my Ariston oven myself?
A knowledgeable DIYer can inspect the wiring connectors and harness between the power supply board and the main control board for obvious damage or loose connections. However, if the fault persists, replacing the power supply board requires working inside the oven's electrical enclosure, which involves mains voltage components. For safety, this repair is best handled by a qualified appliance technician.
Is it safe to use my Ariston oven when it shows ER70?
An ER70 fault typically prevents the oven from operating normally, as the communication breakdown causes the control system to halt. You should not attempt to bypass the error or force the oven to run while this fault is active. Discontinue use and have the oven inspected before cooking with it again.
Will resetting my Ariston oven clear the ER70 error?
A power reset by switching the oven off at the circuit breaker for several minutes may temporarily clear the display, but ER70 caused by a defective power supply board will return because the underlying hardware fault remains. A reset is not a repair and the fault code will reappear once the oven attempts normal communication again.
How much does it cost to repair an Ariston oven showing ER70?
Repair costs depend on parts pricing and local labor rates. A replacement power supply board typically falls in the range of $80 to $200 or more depending on availability, and a technician's labor for diagnosis and replacement can add $100 to $250 to the total. Getting a quote from a certified technician before proceeding is recommended to weigh repair cost against appliance age.

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