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Error code reference

Goodman Air Conditioner Error Code C3

Indoor Coil is freezing up.

Goodman codesGoodman air conditioner codes

Indoor Coil is freezing up.

First step from the service manual

Clean filter, Check for fan and blower operation, Check for Refrigerant loss or Restricted capillary tube.

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

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What C3 means on a Goodman air conditioner

The C3 error code on a Goodman air conditioner indicates that the indoor evaporator coil is freezing up. This occurs when the coil surface temperature drops below 32 degrees Fahrenheit, causing moisture in the air to form ice on the coil fins and refrigerant lines. When ice accumulates, airflow through the coil becomes progressively blocked, reducing the system's ability to absorb heat and deliver conditioned air to the living space. Left unaddressed, a frozen coil can lead to compressor damage due to liquid refrigerant returning to the compressor.

The most common cause of coil freeze-up is restricted airflow. A clogged air filter is the first component to inspect, as a dirty filter starves the evaporator coil of warm return air, causing coil temperatures to fall too low. Blower motor or fan failures produce the same result by reducing air movement across the coil. Both conditions should be assessed before assuming a refrigerant issue.

Refrigerant-related causes are also significant contributors. Low refrigerant charge due to a system leak causes the evaporator pressure to drop, lowering the coil temperature abnormally. A restricted capillary tube or metering device can create a similar pressure drop, producing a freeze condition even when refrigerant charge is correct. Diagnosing between a refrigerant leak and a restricted capillary tube requires gauges to measure suction and discharge pressures, and refrigerant work must be performed by a certified technician.

Source: manufacturer service documentation.

Common causes of C3

  1. 01

    Dirty or Clogged Air Filter

    Part replacement

    A clogged filter restricts warm return air from reaching the evaporator coil, causing coil temperatures to drop below freezing. Inspect and replace the filter as the first step before any other diagnostics.

  2. 02

    Blower Motor or Fan Failure

    Part replacement

    If the indoor blower motor is not operating at full speed or has failed entirely, airflow across the coil is insufficient to prevent freezing. Verify the blower is running and delivering adequate airflow at the supply registers.

  3. 03

    Low Refrigerant Charge Due to a Leak

    Part replacement

    A refrigerant leak reduces system pressure on the suction side, causing the evaporator coil to operate at abnormally low temperatures and freeze. This requires a certified technician to locate the leak, repair it, and recharge the system.

  4. 04

    Restricted Capillary Tube or Metering Device

    Part replacement

    A blocked or partially restricted capillary tube limits refrigerant flow into the evaporator, dropping suction pressure and coil temperature below the freezing point. Manifold gauge readings showing abnormally low suction pressure with a normal or full refrigerant charge can indicate this condition.

  5. 05

    Extremely Low Ambient or Return Air Temperature

    Wiring / connection

    Operating the air conditioner when indoor or outdoor temperatures are unusually low can reduce heat load on the coil enough to cause freezing. This is a situational cause and does not necessarily indicate a component failure.

See the test procedure for each cause

Frequently asked questions about C3

What does C3 mean on a Goodman air_conditioner?
The C3 code on a Goodman air conditioner means the indoor evaporator coil is freezing up. Ice forming on the coil blocks airflow and prevents the system from cooling effectively. Common causes include a dirty air filter, a failed blower, low refrigerant, or a restricted capillary tube. The system should be turned off and allowed to thaw before diagnosing the root cause.
How do I fix a C3 error on my Goodman air conditioner?
Start by turning the system off and switching the fan to the ON position to help thaw the coil, which can take one to several hours. Check and replace the air filter if it is dirty, and confirm the blower fan is running properly. If the coil refreezes after these steps, a refrigerant leak or restricted capillary tube is likely the cause and a certified HVAC technician should be contacted to perform pressure testing and refrigerant service.
Is it safe to run my Goodman AC when a C3 error is displayed?
Running the system with a C3 error is not recommended. A frozen coil blocks airflow and forces the compressor to work under abnormal conditions, which can cause liquid refrigerant to return to the compressor and result in compressor failure. Turn the unit off and allow the coil to thaw completely before attempting to restart the system.
Will resetting the Goodman air conditioner clear the C3 error?
Resetting the unit may temporarily clear the code, but if the underlying cause is not corrected the coil will freeze again and the error will return. A reset should only be performed after the coil has fully thawed and the root cause, such as a dirty filter or airflow problem, has been addressed. If the code returns after a reset, professional diagnostic service is needed.
How much does it cost to repair a Goodman AC with a C3 freeze-up error?
Repair costs vary widely depending on the cause. Replacing an air filter is inexpensive, typically in the range of a few dollars to around twenty dollars. Blower motor replacement can run anywhere from a few hundred to over five hundred dollars depending on parts and labor. Refrigerant leak repairs, including locating the leak, sealing it, and recharging the system, can range from a few hundred to over one thousand dollars depending on the severity and location of the leak.

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