GE Oven Error Code C4

C4 on a GE oven means the main control board has detected a communication failure with the lower relay board. The lower relay board is responsible for controlling the heating elements in the lower oven cavity. The fault can be caused by a loose harness connection, damaged wiring, or a failed relay board. The oven will typically not operate normally while this code is active.

A C4 error indicates that the main control board cannot communicate with the lower relay board, which means the oven may not control its heating elements properly. Using the oven in this condition is not recommended, as the control system may be unable to regulate temperature or shut off heating elements correctly. The oven should be kept off until the fault is diagnosed and repaired.

If the fix is simply reseating a loose connector, there may be no parts cost at all, though a service call will typically run between $75 and $150 for the diagnostic visit. If the lower relay board needs replacement, parts costs can range from $80 to $200 or more depending on the specific model, plus labor if a technician performs the repair. Harness replacement costs will fall somewhere in between, depending on part availability and the extent of the damage.

The first step is always inspecting the wiring harness and connectors between the main board and the lower relay board, which is a task many experienced DIYers can perform after disconnecting power to the unit. If the harness is intact and connectors are secure, resolving the fault will require replacing the lower relay board, which involves working inside the control area of the oven. Anyone uncomfortable working around electrical components should contact a qualified appliance technician.

Resetting the oven by cutting power at the breaker for a few minutes may temporarily clear the C4 code, but it will return if the underlying communication problem has not been corrected. A persistent C4 code after a reset points to a real hardware fault in the harness or the lower relay board that needs to be physically inspected and repaired.