LG Microwave Error Code E-51

E-51 indicates an EEPROM open error, which means the microwave control board cannot communicate with its onboard memory chip. This chip stores operational settings and is required for normal function. The error is typically caused by a missing, incorrect, or failed EEPROM chip. The two compatible chip types for LG microwaves displaying this code are the R4LCO40 and the 24LCO4.

A basic power reset, such as unplugging the unit for a few minutes, will not clear the E-51 error if the underlying EEPROM problem remains. The error will return immediately on startup because the control board checks EEPROM communication during its initialization sequence. The fault can only be resolved by installing a functioning, correct EEPROM chip.

If only the EEPROM chip requires replacement, parts cost is generally low, typically in the range of a few dollars to around $20 depending on the source. If professional labor is involved, total repair costs can range from $75 to $200 or more depending on the service provider and whether any additional components such as the control board need replacement.

Start by checking which EEPROM chip is installed and confirming it is either the R4LCO40 or the 24LCO4. If the wrong chip is present, replace it with one of the correct types and restart the microwave. If the correct chip is already installed and the error continues, the chip has likely failed and should be replaced. Persistent errors after chip replacement may point to a control board issue.

The microwave will not operate normally while displaying E-51, as the control board has halted function due to the memory fault. You should not attempt to force operation. The unit should remain unplugged until the EEPROM issue is diagnosed and corrected.