Dacor Oven Error Code L43

L43 means the lower relay board is not detecting a zero crossing signal, which is a timing reference the board needs to switch heating relays correctly within the AC power cycle. This fault is flagged when the control system loses communication with the zero crossing circuit on the lower relay board. It typically points to a connection issue at connector S19 or a failed relay board.

It is not recommended to continue using the oven while the L43 fault is active. The zero crossing signal is used to synchronize relay switching, and operating without it can cause improper relay timing, which may lead to premature relay failure or other component damage. The oven should be repaired before resuming normal use.

If only the S19 connector needs to be reseated, there may be no parts cost involved, though a service call fee typically applies and can range from $75 to $150 depending on your area. If the lower relay board needs to be replaced, the part cost can range from $150 to $350 or more depending on the specific model, with total repair costs including labor generally falling between $250 and $500.

The first diagnostic step is to check and secure the connections at connector S19 on the lower relay board, which does not require replacing any parts. If the connections are intact and secure but the fault persists, the lower relay board will need to be replaced, which is a more involved repair. Technicians comfortable with appliance disassembly and electrical connectors can often perform this repair, but working near high-voltage components carries risk and caution is advised.

A power reset may temporarily clear the fault display, but if the underlying issue at connector S19 or on the relay board is not corrected, the L43 code will return once the oven attempts to operate. A reset alone is not a fix and should not be used as a substitute for diagnosing the root cause.