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Error code reference

Dacor Range Oven Cooktop Error Code C42

Heritage: E2 checksum failure on control board

Dacor codesDacor range oven cooktop codes

Heritage: E2 checksum failure on control board - calculated E2 checksum does not agree with stored E2 checksum.

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What C42 means on a Dacor range oven cooktop

The C42 error code on Dacor Heritage ranges and ovens signals an E2 checksum failure on the main control board. EEPROM (E2) is a type of non-volatile memory built into the control board that stores critical configuration data, calibration settings, and operational parameters. A checksum is a calculated numerical value derived from the contents of that memory. When the control board performs a checksum verification, it recalculates the checksum from the current memory contents and compares it against the value previously stored. If the two values do not match, the board flags a C42 fault, indicating that the stored data has become corrupted or unreadable.

This type of failure typically points to a problem within the control board itself. The EEPROM chip may have developed a fault due to age, voltage irregularities, or electrical transients such as power surges. In some cases, a momentary power interruption or brownout during a write cycle can corrupt the stored checksum value, leading to this error on the next power-up. The failure is internal to the control board and cannot be corrected by simply adjusting wiring or external components.

Because the checksum mismatch means the control board cannot confirm the integrity of its stored configuration data, the board may refuse to operate normally until the issue is resolved. A power reset may temporarily clear the fault in some cases, but if the EEPROM has genuinely failed or the data is persistently corrupted, the error will return. Resolving C42 reliably almost always requires replacing the main control board.

Source: manufacturer service documentation.

Common causes of C42

  1. 01

    Failed or corrupted EEPROM on the control board

    Part replacement

    The EEPROM chip on the control board has degraded or developed an internal fault, causing the stored checksum to no longer match the calculated value. This is the most common root cause and requires control board replacement.

  2. 02

    Power surge or electrical transient

    Part replacement

    A voltage spike or surge can corrupt data in EEPROM memory, especially if it occurs during a write cycle. Check if the error appeared after a power outage or storm event.

  3. 03

    Power interruption during a write cycle

    Wiring / connection

    If power was lost or interrupted at the exact moment the board was writing data to EEPROM, the stored checksum can become invalid. A one-time reset may resolve this if no permanent chip damage occurred.

  4. 04

    Aging or worn control board

    Part replacement

    Over time, EEPROM memory cells can degrade and lose their ability to reliably retain data. This is more common on older units and typically results in a persistent, recurring C42 fault.

See the test procedure for each cause

Frequently asked questions about C42

What does C42 mean on a Dacor range, oven, cooktop?
C42 on a Dacor Heritage appliance indicates an E2 checksum failure on the main control board. The board calculates a checksum from its EEPROM memory contents and compares it to the stored checksum value. When those two values do not agree, the board triggers C42, signaling that its internal memory data is corrupted or unverifiable.
Will resetting the power clear the C42 error on my Dacor oven?
A power reset may temporarily clear the C42 error if the corruption was caused by a one-time event such as a brief power interruption. However, if the EEPROM chip itself has failed or the data corruption is persistent, the error will return after the reset. A recurring C42 after multiple resets indicates the control board needs to be replaced.
Is it safe to use my Dacor oven while it is showing a C42 error?
A C42 fault means the control board cannot verify the integrity of its stored configuration and calibration data. Using the appliance in this state is not recommended, as the board may not operate with accurate settings. It is best to avoid using the oven until the fault is diagnosed and resolved.
How much does it cost to fix a C42 error on a Dacor range or oven?
Because C42 almost always requires replacing the main control board, repair costs typically fall in the range of $200 to $600 or more, depending on the specific Heritage model and whether you use a professional technician or perform the replacement yourself. Labor costs vary by region and service provider.
Can I fix the C42 error myself, or do I need a technician?
If a single power interruption caused the error, a power reset is worth attempting first and requires no technical skill. If the error persists, the repair involves replacing the main control board, which requires comfort working with appliance electronics and safely disconnecting power. Many experienced DIYers can handle a control board swap, but if you are uncertain, a qualified appliance technician is the safer choice.

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