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Error code reference

Dacor Oven Error Code C42

E2 checksum failure on control board

Dacor codesDacor oven codes

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 oven

The C42 error code on a Dacor oven indicates an E2 (EEPROM) checksum failure on the control board. The EEPROM is a small non-volatile memory chip embedded on the electronic control board that stores critical configuration data, calibration settings, and operational parameters for the oven. During normal operation, the control board continuously calculates a checksum value based on the data stored in EEPROM and compares it against a previously stored reference checksum. When these two values do not match, the board flags a C42 fault, signaling that the stored data may be corrupted or unreadable.

This type of fault is almost always rooted in the electronic control board itself rather than in external wiring or sensors. EEPROM corruption can result from power surges or voltage spikes that write invalid data to memory cells, gradual degradation of the EEPROM chip over time, or a manufacturing defect in the memory component. In some cases, a brief power interruption during a write cycle can leave the EEPROM in an inconsistent state, causing the checksum mismatch.

Because the checksum failure is internal to the control board, a power reset may temporarily clear the fault if the corruption was caused by a transient event. However, if the EEPROM chip itself has failed or the board firmware has become permanently corrupted, the error will return. In most cases, resolving C42 requires replacement of the electronic control board, as the EEPROM is soldered directly to the board and is not a field-replaceable component.

Source: manufacturer service documentation.

Common causes of C42

  1. 01

    EEPROM chip failure on control board

    Part replacement

    The EEPROM memory chip on the control board can degrade or fail over time, causing its stored checksum to no longer match the calculated value. This is the most common root cause and typically requires full control board replacement.

  2. 02

    Power surge or voltage spike

    Part replacement

    A sudden surge in electrical supply voltage can corrupt data written to the EEPROM during a write cycle. Check the home circuit and surge protection; if the board was damaged by a surge, replacement is necessary.

  3. 03

    Power interruption during EEPROM write cycle

    Wiring / connection

    If power was cut while the board was actively writing data to EEPROM, the stored checksum and the data can become mismatched. A power reset may resolve this if the corruption is not permanent.

  4. 04

    Control board firmware corruption

    Part replacement

    The firmware or configuration data stored in EEPROM can become corrupted due to component aging or electrical stress, preventing the board from validating its own memory. Board replacement is the standard remedy.

See the test procedure for each cause

Frequently asked questions about C42

What does C42 mean on a Dacor oven?
The C42 error code on a Dacor oven indicates an E2 checksum failure on the electronic control board. This means the control board calculated a checksum value from its EEPROM memory that does not agree with the checksum value previously stored in that memory. The fault points to corrupted or unreadable data in the control board's internal EEPROM chip.
Will resetting the oven clear the C42 error code?
A power reset may temporarily clear the C42 code if the EEPROM corruption was caused by a transient event such as a brief power interruption. To reset, turn off the circuit breaker supplying the oven for several minutes, then restore power. If the error returns after the reset, the EEPROM chip or control board has likely sustained permanent damage and will need to be replaced.
Is it safe to use my Dacor oven while the C42 error is displayed?
Operating the oven with a C42 fault is not recommended. Because the error indicates corrupted control board memory, the oven's settings, temperature calibration, and safety logic may not function reliably. It is best to avoid using the appliance until the control board has been inspected and the fault resolved.
How do I fix the C42 error on a Dacor oven?
Start by performing a power reset at the circuit breaker to rule out a transient memory error. If the code returns, the electronic control board will need to be replaced, as the EEPROM chip is soldered directly to the board and cannot be serviced separately in the field. A qualified appliance technician can confirm the diagnosis and source the correct replacement board.
How much does it cost to repair a Dacor oven showing a C42 error?
Repair costs depend primarily on the price of the replacement control board and labor rates in your area. Control board replacements on Dacor ovens typically range from roughly $300 to $700 or more for parts and labor combined, depending on the specific model and local service rates. Getting a diagnostic estimate from a certified technician before committing to the repair is advisable.

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