Goodman Air Conditioner Error Code C4

Code C4 means the indoor evaporator coil has frozen over. Ice has built up on the coil, blocking airflow and preventing the system from cooling properly. The primary causes are a dirty air filter, a blower or fan problem, low refrigerant, or a restricted capillary tube. The system should be turned off to allow the ice to thaw before any diagnostic work begins.

No, you should not continue running the system while the coil is frozen. Operating the unit with a frozen coil forces the compressor to work under abnormal conditions, which can cause compressor overheating or failure. Turn the system off immediately and allow it to fully thaw before attempting to restart or diagnose it.

Repair costs vary widely depending on the cause. Replacing an air filter is a low-cost fix in the range of a few dollars to around $30. A blower motor replacement can run from $150 to $450 or more depending on the motor and labor. Refrigerant leak repair and recharge typically falls in the range of $200 to $600 or higher depending on the severity of the leak and the refrigerant type required.

Start by turning the system off and switching the fan to the on position to help thaw the coil. Once thawed, check and replace the air filter if it is dirty, and confirm the indoor blower fan is operating correctly. If those checks pass, a licensed HVAC technician should check system refrigerant pressure and inspect the capillary tube for restriction, as both require specialized tools and refrigerant handling certifications.

Resetting the unit may clear the code temporarily, but the code will return if the underlying cause is not corrected. A dirty filter, fan failure, refrigerant leak, or restricted capillary tube will continue to cause the coil to freeze regardless of resets. Address the root cause before restarting the system to avoid compressor damage.