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Error code reference

Goodman Air Conditioner Error Code L6

Discharge Air Too Hot.

Goodman codesGoodman air conditioner codes

Discharge Air Too Hot.

First step from the service manual

Clean Filter or Remove Air Blockage.

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

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What L6 means on a Goodman air conditioner

The L6 error code on a Goodman air conditioner indicates that the discharge air temperature has exceeded safe operating limits. The discharge air is the conditioned air leaving the evaporator coil and being pushed through the supply ducts into the living space. When this air becomes excessively hot, the system interprets it as a condition where cooling capacity is severely compromised, triggering the L6 fault to protect internal components from damage due to prolonged inefficient operation.

The most common root cause of this fault is restricted airflow across the evaporator coil. When airflow is blocked, heat exchange cannot occur efficiently, and the air passing through the system retains too much heat before reaching the supply registers. A clogged air filter is the primary suspect, as a heavily loaded filter can reduce airflow dramatically. Beyond the filter, collapsed ductwork, blocked return grilles, or a failed blower motor can all produce the same restriction effect.

Additional causes include low refrigerant charge, a dirty evaporator coil, or a malfunctioning metering device, all of which reduce the system's ability to absorb heat from the air passing over the coil. If the airflow path is confirmed clear but the L6 fault persists, refrigerant-side diagnostics including pressure testing should be the next step. A licensed HVAC technician should handle refrigerant-related repairs.

Source: manufacturer service documentation.

Common causes of L6

  1. 01

    Clogged or Dirty Air Filter

    Part replacement

    A heavily loaded air filter restricts airflow across the evaporator coil, preventing proper heat exchange. Check and replace the filter if it appears gray, matted, or visibly clogged.

  2. 02

    Blocked Return or Supply Vents

    Wiring / connection

    Furniture, debris, or closed registers blocking return grilles or supply vents can reduce airflow enough to trigger the L6 fault. Inspect all grilles and registers throughout the home.

  3. 03

    Dirty Evaporator Coil

    Wiring / connection

    A coil coated with dust and debris insulates the refrigerant from the airstream, reducing cooling capacity. This typically requires professional cleaning with coil cleaner.

  4. 04

    Low Refrigerant Charge

    Part replacement

    Insufficient refrigerant reduces the system's ability to absorb heat, resulting in warmer discharge air and an L6 fault. A technician must perform pressure testing and inspect for leaks.

  5. 05

    Failed or Weak Blower Motor

    Part replacement

    A blower motor operating below normal speed or failing intermittently will not move adequate air volume across the evaporator coil. Listen for unusual motor sounds and verify airflow at the registers.

See the test procedure for each cause

Frequently asked questions about L6

What does L6 mean on a Goodman air_conditioner?
The L6 code means the discharge air temperature is too high, indicating the system is not cooling the air adequately before pushing it into the ductwork. This is typically caused by restricted airflow or a refrigerant-side issue. The system triggers this fault to alert you that cooling performance is compromised. Start by checking and replacing the air filter and clearing any obstructions from vents.
How do I fix the L6 error on my Goodman air conditioner?
Begin by replacing a dirty air filter and confirming that all return and supply vents are open and unobstructed. If airflow appears normal after those steps, inspect the evaporator coil for dirt buildup and clean it if needed. If the fault persists after restoring proper airflow, contact a licensed HVAC technician to check the refrigerant charge and metering device.
Will resetting my Goodman air conditioner clear the L6 code?
A reset may temporarily clear the L6 fault, but the code will return if the underlying cause is not corrected. Simply resetting the unit without addressing the airflow restriction or refrigerant issue will allow the problem to continue and could lead to further component wear. Always resolve the root cause before or alongside resetting the system.
Is it safe to run my Goodman air conditioner with an L6 error?
Continuing to operate the unit with an L6 fault is not recommended. Prolonged running under high discharge air temperature conditions can stress the compressor and other components, potentially leading to more costly damage. Shut the system down, address the airflow or refrigerant issue, and then resume operation.
How much does it cost to repair a Goodman air conditioner showing an L6 error?
Repair costs vary depending on the cause. A filter replacement is generally inexpensive, typically in the range of $5 to $30 for the part. Professional coil cleaning may range from $75 to $200. If the fault is related to a refrigerant leak or a failed blower motor, repair costs can range from $150 to $600 or more depending on the extent of the work and local labor rates.

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