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Refrigerator Main control board: What It Does and Signs It's Failing

The board that runs the compressor, fans, defrost heater, damper and ice maker, usually in a control box on top of the fridge, at the back or in the machine compartment. Inverter models add a separate board that drives the compressor. On some models, LG among them, the relay that switches the compressor sits on this board; older fridges without electronic controls use a start relay plugged onto the compressor instead.

How it works

The board reads the sensors and switches each load on and off. When a reading is out of range it stores a code.

Signs it is failing

• Several unrelated parts not running
• Compressor relay or inverter codes
• No cooling with power to the fridge
• Burn marks or a burned smell near the board
• Codes after a power surge

Relay, inverter and power codes often clear after a power cycle; if they come back, the board, the inverter board or the compressor needs testing. Power-failure alerts usually mean an outage or a loose plug, not a bad board.

Can you replace it yourself?

Make sure the fridge is plugged straight into a working wall outlet; LG says not to use a power strip, and an extension cord is no better. Samsung asks you not to unplug or clear a code unless its steps tell you to, because that makes diagnosis harder. Board diagnosis and replacement is tech work; don't open the board.

Buying the right part

Fridge boards are expensive, so get the diagnosis confirmed and read the seller's return terms for installed electrical parts before you buy the OEM board.

Error codes linked to the main control board

• PFPower failureFrigidaire
• OP / SHTemperature sensor open or shortedFrigidaire
• SY EFEvaporator fan circuit failureFrigidaire
• SY CE / SY CFControl board and display not communicatingFrigidaire
• PFPower was interruptedGE
• dEDefrost system not working properlyGE
• Er dHDefrost cycle failedLG
• Er COMain board and display are not communicatingLG
• Er 22Compressor relay problemLG
• 88 88Display did not boot correctly after a power cutSamsung
• 83ECompressor power problem (surge or brownout)Samsung
• 84CCompressor lockSamsung
• PC ERCommunication error between fridge partsSamsung
• F3E1Refrigerator compartment temperature sensor faultWhirlpool
• F3E2Freezer temperature sensor faultWhirlpool
• F3E4Freezer evaporator (defrost) sensor faultWhirlpool
• F4E1Freezer defrost heater problemWhirlpool
• F6E1Main control and display have stopped communicatingWhirlpool
• F7E1Compressor not runningWhirlpool
• FAE1Evaporator fan faultWhirlpool
• FAEd / FAE6Air damper or air duct blockedWhirlpool
• POPower outage warningWhirlpool

Last reviewed 2026-10-19.