mypros+
Error code reference

Thermador Cooktop Error Code E0302

Right ADB relay board error in the microcontroller's internal memory (EEPROM)

Thermador codesThermador cooktop codes

Right ADB relay board error in the microcontroller's internal memory (EEPROM) — content corrupted beyond recovery.

First step from the service manual

Replace the right relay board (ADB).

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

MyPros+ Max

Get the full diagnostic procedure for E0302.

  • 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
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What E0302 means on a Thermador cooktop

Error code E0302 on a Thermador cooktop indicates a critical failure in the right ADB (Analog Distribution Board) relay board's internal EEPROM memory. EEPROM, which stands for Electrically Erasable Programmable Read-Only Memory, is used by the microcontroller on the relay board to store configuration data, calibration values, and operational parameters. When this memory becomes corrupted beyond recovery, the board can no longer function reliably, and the cooktop's control system flags the fault as E0302.

The right ADB relay board is responsible for managing relay switching operations on the right side of the cooktop, controlling power delivery to the corresponding heating elements. EEPROM corruption of this severity is typically not caused by normal wear but rather by events such as voltage spikes, power surges, or an abrupt interruption of power during a write cycle to the memory chip. In some cases, a manufacturing defect in the memory chip itself can lead to this condition over time.

Because the EEPROM corruption is described as beyond recovery, software resets or power cycling will not resolve this error. The microcontroller cannot repair or reinitialize the corrupted memory contents through normal operation. The direct corrective action is physical replacement of the right ADB relay board. Attempting to continue operating the cooktop with this fault active is not recommended, as the relay board may not correctly control heating element power in a predictable way.

Source: manufacturer service documentation.

Common causes of E0302

  1. 01

    EEPROM memory chip failure on the right ADB relay board

    Part replacement

    The memory chip on the right relay board has failed internally, corrupting stored data beyond what the microcontroller can recover. This is the primary cause of E0302 and requires board replacement.

  2. 02

    Power surge or voltage spike

    Part replacement

    A sudden spike in incoming voltage can corrupt or permanently damage EEPROM memory during a write cycle. Check whether the cooktop is on a properly rated, dedicated circuit with appropriate surge protection.

  3. 03

    Abrupt power interruption during memory write cycle

    Part replacement

    If power was cut suddenly while the board's microcontroller was writing data to EEPROM, the memory contents can become corrupted. This scenario often leaves the board non-recoverable.

  4. 04

    Manufacturing defect in the relay board

    Part replacement

    In some cases, the EEPROM chip may have had a latent defect from the factory that degrades over time and eventually leads to full corruption. This is less common but is a known failure mode for relay boards.

See the test procedure for each cause

Frequently asked questions about E0302

What does E0302 mean on a Thermador cooktop?
E0302 indicates that the EEPROM memory on the right ADB relay board has become corrupted beyond recovery. The microcontroller on that board can no longer read or use the data stored in its internal memory. This prevents the right side of the cooktop from operating correctly. The board must be replaced to clear this fault.
Can I fix E0302 myself on a Thermador cooktop?
Replacing the right ADB relay board is the required repair for E0302, and it involves working with the internal components of the cooktop. A technician with appliance repair experience can perform this replacement, but because it involves electrical components and disassembly of the unit, it is generally recommended to have a qualified technician handle the job.
Will resetting my Thermador cooktop clear the E0302 error?
No, a reset will not clear E0302. The error is caused by permanent EEPROM memory corruption on the right relay board, which cannot be repaired by cycling power or performing a soft reset. The fault will return immediately because the underlying hardware failure remains present. Board replacement is the only resolution.
Is it safe to use my Thermador cooktop while E0302 is active?
It is not recommended to continue using the cooktop with E0302 active. A corrupted relay board may not control the right-side heating elements predictably, which could result in elements not shutting off correctly or behaving erratically. Discontinue use until the right ADB relay board has been replaced.
How much does it cost to repair a Thermador cooktop showing E0302?
Repair costs will vary depending on your region and the service provider, but typically include the cost of the replacement right ADB relay board plus labor. Parts and labor combined generally fall in the range of $200 to $500 or more, depending on parts availability and technician rates. Getting a diagnostic estimate from a certified technician before authorizing the repair is advisable.

Related Thermador cooktop codes

All Thermador cooktop codes
View all 129 Thermador cooktop codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass