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Error code reference

LG Oven Error Code H-4

Lower broil heater error detected during self-diagnosis.

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Lower broil heater error detected during self-diagnosis.

First step from the service manual

Check the lower broil heater wire on the Wall Main PCB (T206, T207) for correct connection.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What H-4 means on a LG oven

The H-4 error code on an LG oven indicates that a lower broil heater fault has been detected during the appliance's self-diagnostic routine. This error is specific to the lower broil heating element circuit, which the Wall Main PCB monitors for proper electrical continuity and performance. When the control board runs its self-check sequence, it sends a signal through the lower broil heater circuit and evaluates the response. If the board receives an out-of-range reading or no reading at all, it flags the H-4 code and halts operation to prevent potential damage or hazard.

The Wall Main PCB connects to the lower broil heater through terminal points T206 and T207. These connectors are the first place to inspect, as loose, corroded, or improperly seated wire connections at these terminals are a common cause of the fault. A poor connection at either terminal can interrupt the circuit and produce the same error as a fully failed heating element, making connector inspection a critical first step before replacing any components.

If the wiring connections at T206 and T207 are secure and undamaged, the diagnostic focus should shift to the lower broil heater element itself. A failed or open heating element will break the circuit entirely, triggering the H-4 fault. The Wall Main PCB can also be responsible if it is unable to correctly read or supply voltage to the heater circuit, though board failure is typically the least common cause compared to element or wiring issues.

Source: manufacturer service documentation.

Common causes of H-4

  1. 01

    Loose or disconnected wiring at T206 or T207

    Wiring / connection

    The wire connectors on the Wall Main PCB at terminals T206 and T207 may have come loose, partially disconnected, or corroded over time. Inspecting and reseating these connectors is the recommended first step and can resolve the error without any parts replacement.

  2. 02

    Failed lower broil heating element

    Part replacement

    The lower broil element may have burned out or developed an open circuit, preventing the PCB from detecting a valid reading. A failed element will typically show visible damage such as blistering or a break in the element coil, and can be confirmed with a continuity test.

  3. 03

    Damaged or burned wiring harness

    Part replacement

    The wiring between the Wall Main PCB and the lower broil element may have been damaged by heat exposure, pinching, or rodent activity. Inspect the full length of the harness for melted insulation, breaks, or burn marks.

  4. 04

    Corroded or damaged terminal connectors

    Wiring / connection

    Corrosion at the T206 or T207 terminals on the PCB, or on the corresponding wire connectors, can create enough resistance to disrupt the circuit signal. Cleaning the terminals or replacing the connector ends may restore proper function.

  5. 05

    Faulty Wall Main PCB

    Part replacement

    If all wiring, connectors, and the heating element test as functional, the Wall Main PCB itself may have failed and is incorrectly reading the lower broil heater circuit. Board replacement is typically the last step after all other causes have been ruled out.

See the test procedure for each cause

Frequently asked questions about H-4

What does H-4 mean on a LG oven?
The H-4 code means the LG oven's self-diagnostic system has detected an error in the lower broil heater circuit. The Wall Main PCB monitors this circuit and triggers the code when it receives an unexpected or absent signal from the heater. The fault can stem from a wiring connection issue at PCB terminals T206 or T207, a failed heating element, or less commonly, a defective control board.
Can I fix the H-4 error myself?
Some causes of the H-4 error are within reach of a knowledgeable DIYer. Checking and reseating the wire connections at terminals T206 and T207 on the Wall Main PCB requires no special tools and no parts. However, replacing a heating element or control board involves working with high-voltage components, so anyone uncomfortable with electrical repairs should contact a qualified appliance technician.
Is it safe to use my LG oven when the H-4 code is displayed?
It is not recommended to continue using the oven while the H-4 error is active. The code indicates a fault in the lower broil heater circuit, and operating the appliance with an unresolved electrical issue could pose a safety risk. The oven should be inspected and repaired before resuming normal use.
Will resetting the oven clear the H-4 error?
A power reset by unplugging the oven or switching off the circuit breaker may temporarily clear the H-4 code, but it will return if the underlying fault is not repaired. The error is generated by the self-diagnostic routine, so any remaining wiring fault, failed element, or board issue will trigger the code again on the next diagnostic cycle.
How much does it cost to repair the H-4 error on a LG oven?
Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector, there may be no parts cost, though a service call fee could apply if a technician performs the work. Replacing a lower broil heating element typically ranges from around $50 to $150 for parts, while a Wall Main PCB replacement can range from $100 to $300 or more for the part alone, plus labor costs if professionally serviced.

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