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Error code reference

Dacor Range Oven Cooktop Error Code L42

Relay board (lower oven)

Dacor codesDacor range oven cooktop codes

Relay board (lower oven) - failure on relay board.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
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What L42 means on a Dacor range oven cooktop

The L42 error code on a Dacor range or oven indicates a failure detected on the relay board associated with the lower oven. The relay board is a dedicated control board that houses multiple relays responsible for switching power to the lower oven's heating elements, including the bake and broil elements. When the control system detects an abnormal condition on this board, such as a relay that has failed open or closed, a shorted relay coil, or a board-level fault that prevents proper switching, it logs the L42 code and typically disables the lower oven to prevent unsafe operation.

Relay failures on these boards are commonly caused by electrical stress over time. Relays are mechanical and electrical components that cycle on and off thousands of times during normal use. Eventually, their contact points can arc, weld together, or corrode, causing the relay to either stick in the closed position (allowing continuous power to a heating element) or fail open (preventing power from reaching the element entirely). Either condition is detectable by the oven's control system and will trigger the L42 fault.

The relay board itself may also fail due to a cracked solder joint, a failed capacitor or resistor on the board, or damage caused by a power surge. In some cases, the wiring harness connecting the relay board to the main control board or to the heating elements can develop a short or open connection that the system interprets as a relay board fault. A thorough diagnosis should include visual inspection of the relay board for burn marks or damaged components, continuity checks on the wiring harness, and verification that supply voltage to the board is within the correct range.

Source: manufacturer service documentation.

Common causes of L42

  1. 01

    Failed relay on the relay board

    Part replacement

    One or more relays on the lower oven relay board has failed, either welded shut or burned open. This is the most direct cause of L42 and can often be identified by visible burn marks, a distinctive burning smell, or a relay that audibly clicks abnormally.

  2. 02

    Relay board internal component failure

    Part replacement

    A capacitor, resistor, or solder joint on the relay board may have failed, causing the board to malfunction even if the relays themselves appear intact. Visual inspection may reveal bulging capacitors, cracked solder joints, or scorch marks on the board surface.

  3. 03

    Wiring harness fault

    Wiring / connection

    A damaged, shorted, or disconnected wire in the harness running between the relay board and the main control board or heating elements can trigger this fault. Inspect all connectors and wiring routed near the lower oven cavity for heat damage or loose terminals.

  4. 04

    Power surge or voltage irregularity

    Wiring / connection

    A voltage spike or unstable power supply can damage relay board components or cause a one-time fault condition. If no physical damage is found, checking the supply voltage at the relay board is a useful diagnostic step.

  5. 05

    Main control board communication fault

    Part replacement

    In some cases, the main control board may incorrectly report a relay board failure due to its own internal fault or a communication error between the two boards. This is less common but should be considered if the relay board tests as functional.

See the test procedure for each cause

Frequently asked questions about L42

What does L42 mean on a Dacor range, oven, cooktop?
The L42 code indicates a failure has been detected on the relay board for the lower oven. The relay board controls power switching to the lower oven's heating elements. This fault disables the lower oven to prevent unsafe heating conditions and requires diagnosis and likely repair of the relay board or associated wiring.
Can I reset the L42 code to clear it?
Cycling power to the appliance by turning off the circuit breaker for 60 seconds and restoring it may temporarily clear the code, but if the relay board has a physical failure, the code will return as soon as the lower oven is used again. A reset does not repair the underlying fault. If the code does not return after a reset, monitor the oven closely for signs of abnormal heating behavior.
Is it safe to use my Dacor oven while the L42 code is active?
You should avoid using the lower oven while L42 is active. A failed relay stuck in the closed position could cause a heating element to remain energized continuously, creating a fire risk or damaging other components. A relay failed open means the oven will not heat correctly, which is a lesser safety concern but still indicates a component that requires service.
How do I fix the L42 error on a Dacor oven?
Fixing L42 typically requires inspecting and testing the lower oven relay board for failed relays, burned components, or damaged solder joints. The wiring harness connected to the relay board should also be checked for shorts or loose terminals. In most cases, the relay board will need to be replaced. This repair involves working near high-voltage components and is best performed by a qualified appliance technician.
How much does it cost to repair the L42 error on a Dacor oven?
Repair costs vary depending on whether the fix requires a new relay board, wiring repairs, or replacement of additional components. Parts costs for relay boards on Dacor ovens typically range from roughly 80 to 250 dollars depending on the model, and professional labor can add another 100 to 200 dollars or more. Getting a diagnosis from a technician before ordering parts is recommended to confirm the failed component.

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