LG Microwave F13 Error Code — What It Means
The F13 error code on an LG microwave indicates a voltage error. LG lists F13 alongside F14 and F15 as faults that require professional service rather than a simple user reset. The code signals a problem in the microwave’s voltage-sensing or power-supply path, meaning the control electronics cannot correctly read or regulate the incoming voltage.
Because LG does not publish detailed root-cause diagnostics for F13, service technicians interpret the code as pointing to either incoming line-voltage issues, a failing power-supply circuit on the main control board, or a defective control board that cannot properly interpret voltage. The appliance will typically refuse to operate or shut down to protect itself when this fault is active.
Common Causes
- Failing main control board The PCB that monitors voltage may have developed a fault in its voltage-sensing circuits or power-supply section, causing it to report an F13 error even when line voltage is correct.
- Low or unstable incoming line voltage If your household outlet delivers below-normal or fluctuating voltage, the microwave’s control logic will detect the condition and throw the F13 code.
- Defective power-supply section on the control board Components such as capacitors, diodes, or regulators in the board’s power-supply path can degrade and produce incorrect voltages that trigger the error.
- Loose or corroded wiring harness connections Poor contact at control-power connectors can create intermittent voltage drops that the board reads as a fault condition.
Step-by-Step Fix
- Unplug the microwave from the wall receptacle and leave it disconnected for at least one minute to allow the control board to fully discharge and reset.
- Plug the unit back in and test whether the F13 code returns when you attempt to operate the microwave.
- Check the wall outlet voltage with a multimeter to confirm you have stable household voltage at the receptacle, since LG identifies F13 as a voltage error.
- Inspect the microwave’s power cord and plug for any visible damage, burn marks, or loose prongs that might cause intermittent supply problems.
- Schedule a service call if the code persists after the reset and incoming power checks out, because LG explicitly requires service for the F13 fault.
- During service, the technician will inspect the main control board, power-supply circuits, and wiring harnesses for abnormal readings or damaged components.
- Replace the control board or power-supply section if bench tests or voltage measurements confirm a fault in those components, then verify that the F13 code clears and the microwave operates normally.
Parts Often Needed
| Part | Notes |
|---|---|
| Main control board (PCB) | Amazon | Match the board part number printed on your existing control board or listed in your microwave’s service manual. |
| Wiring harness for control power | Amazon | Order only if inspection shows melted insulation, corroded terminals, or physical damage at the connectors. |
When to Call a Pro
LG requires professional service for the F13 voltage error. If unplugging the microwave for one minute does not clear the code, or if the code returns immediately after a reset, contact an LG-authorized technician. Voltage faults involve the main control board and power-supply circuits that require test equipment and component-level diagnosis. Attempting board-level repairs without proper tools and knowledge risks electric shock and further damage to the appliance.