LG · Oven Minor

F18 — Second meat probe error

On models with two probe inputs (or a second cavity), the secondary probe circuit is open or shorted. Probe cooking on that cavity is disabled.

Keep using it?
Yes — fix when convenient
DIY difficulty
Easy
Verified against
lg.com ↗

How to fix it

  1. Unplug both probes and press CLEAR/OFF.
  2. Test with a known-good OEM probe in the second jack.
  3. Inspect the jack for grease, debris, or bent pins.
  4. If F18 persists with no probe inserted, the receptacle/harness is faulty — replace it.
  5. Replace the probe itself if a known-good probe in the same jack works.

Why it happens

Typical signs: F18 or F-18 on display · Probe cook on the second cavity will not start · Probe icon flashing for the second oven · Standard bake still works

  • Damaged secondary probe cable Tip element or pigtail open from repeated bending.
  • Contaminated cavity-wall jack Grease in the second jack.
  • Probe wrong type for the jack Aftermarket probe with wrong resistance curve.
  • Open wiring or failed jack on the cavity wall Harness from jack to board opened.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • LG oven meat probe (OEM) Common replacement
    Amazon →

More LG oven codes

5b 5b — Sabbath Mode active (not a fault) CF1 CF1 — Left-front cooktop sensor open/short CF2 CF2 — Left-rear cooktop sensor open/short CF3 CF3 — Right-front cooktop sensor open/short CF4 CF4 — Rear Cooktop Sensor Error (Zone Varies by Model) F1 Range F1 — Upper Oven Thermistor Error

All LG codes → All oven codes →

Frequently asked questions

What does the F18 code mean on a LG oven?

On models with two probe inputs (or a second cavity), the secondary probe circuit is open or shorted. Probe cooking on that cavity is disabled.

What causes the F18 code on a LG oven?

Damaged secondary probe cable: Tip element or pigtail open from repeated bending. Contaminated cavity-wall jack: Grease in the second jack. Probe wrong type for the jack: Aftermarket probe with wrong resistance curve.

Is it safe to keep using a LG oven with a F18 error?

Yes — fix when convenient. This is rated a minor-severity fault.

How do I fix F18 on a LG oven?

Unplug both probes and press CLEAR/OFF. Test with a known-good OEM probe in the second jack. Inspect the jack for grease, debris, or bent pins.

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.