LG Microwave F5 Error Code: Damper Switch Error (What to Do)

What the code means

LG's microwave error code guide in its help library, the same chooser that lists F1 (main board), F2 (thermistor), F3 (control panel), F4 (humidity sensor) and F11 (inverter communication), lists F5 as a damper switch error that needs service. The damper is the flap in the vent path of an over-the-range microwave, the kind that sits above a cooktop and doubles as a range hood. A small motor moves it and a switch reports its position back to the main board. LG's service-tech reference for this code puts it plainly: the main board doesn't see the damper motor move when it calls for it, so the problem is either the damper motor or the switch, and the first check is the motor and switch connections. LG's first step for any F code is the same: the symptom may be a temporary error, so unplug the microwave, plug it back in and see whether the code returns, and book an inspection if it does. One note on conflicting tables: Appliance Aid's NeoChef chart lists F-5 as a humidity sensor error, but LG's own NeoChef service manual and help library put the humidity sensor at F4, so on a current LG microwave read F5 as the damper. If your microwave is a countertop model with no vent, check the code again and see our LG F4 page.

Likely causes

• A damper switch that no longer confirms the damper's position (LG's named fault)
• A damper motor that doesn't move the flap when the main board calls for it
• A loose, corroded or damaged connector or wire at the damper motor or switch, which LG's service guidance says to check first
• A damper flap that is stiff or blocked, for example by grease build-up or something lodged in the vent path
• Less often, the main control board not driving the damper motor

Safe DIY checks

1. Unplug the microwave or switch off its breaker for a minute, then restore power. LG says F codes can be temporary errors that clear this way.
2. If F5 came up right after a storm, power cut or new installation, try the reset once more before booking service.
3. Check that nothing is blocking the vent openings on top of or around the microwave, and that the duct or recirculating grille isn't packed with grease or debris you can reach without tools.
4. Clean the grease filters under the microwave as your owner's manual describes, since heavy grease in the vent area can make moving parts stiff.
5. Write down your full model number and the exact code before you call, so the technician brings the right damper parts.
6. Don't open the cabinet to reach the damper switch or motor. A microwave holds a high-voltage capacitor that can stay charged after it is unplugged.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• AC1 LG Microwave AC1
• E10 LG Microwave E10
• F10 LG Microwave F10
• F11 LG Microwave F11
• F3 LG Microwave F3

All LG codes →

Sources

1. LG Help Library: Microwave - Error Code Cause & Solutions (LG's error code chooser; F5 damper switch error, service required; F4 humidity sensor error)
2. LG Error Codes (service-tech reference): MW_F5 Damper Switch Error (main PCB doesn't see the damper motor move when called for; check damper motor and switch connections)
3. LG USA Support: LG Microwave - Troubleshooting an F3 Error (F codes may be temporary errors; unplug, plug back in, call for inspection if the code returns)
4. Fault Code Check: LG F5 microwave fault code (LG publishes F5 as a damper switch error; over-the-range models with a vent damper)
5. Appliance Aid: LG Microwave Fault Code Chart (NeoChef table lists F-5 as a humidity sensor error, which conflicts with LG's F4 listing; noted, not followed)