Sub-Zero Freezer Error Code 43

Error code 43 means the control board has detected a problem with the left refrigerant valve or its wiring circuit. This valve, made by Aweco, controls refrigerant flow in the left cooling circuit and should measure approximately 295 ohms at its coil terminals. The fault indicates the valve or wiring is outside acceptable parameters.

A faulty refrigerant valve can cause the freezer to lose its ability to maintain safe storage temperatures, which creates a food safety risk. It is not recommended to rely on the unit for storing perishables until the fault is diagnosed and repaired. Monitor internal temperatures closely if you must use the freezer briefly before service.

A reset may temporarily clear the code, but it will return if the underlying fault in the valve or wiring has not been corrected. Resetting without repairing the root cause does not restore proper valve operation and can delay a necessary repair while the freezer continues to underperform. The fault should be diagnosed and resolved before relying on the unit.

Basic wiring inspection and connector reseating are tasks a knowledgeable DIYer can perform, but testing the valve coil resistance requires a multimeter and familiarity with the wiring harness layout. Replacing the Aweco dual refrigerant valve involves working near sealed system components, so full valve replacement is best handled by a certified technician. Attempting repairs without proper knowledge can void warranties or cause additional damage.

If only wiring or a connector needs repair, costs are generally in the range of $100 to $250 including labor. Replacing the Aweco dual refrigerant valve typically costs between $200 and $500 or more depending on parts availability and labor rates in your area. A control board replacement, if required, can add additional cost to the repair.