F18 Minor Easy DIY

LG Oven F18 — Second meat probe error

LG Oven · Error code F18

What F18 Means

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.

Symptoms

  • 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

Common Causes

1
Damaged secondary probe cable

Tip element or pigtail open from repeated bending.

2
Contaminated cavity-wall jack

Grease in the second jack.

3
Probe wrong type for the jack

Aftermarket probe with wrong resistance curve.

4
Open wiring or failed jack on the cavity wall

Harness from jack to board opened.

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.

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.

Common replacement LG oven meat probe (OEM) View on 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 — Right-rear cooktop sensor open/short F1 Range F1 — Upper Oven Thermistor Error

All LG codes → All oven codes →

Verified against manufacturer documentation: lgparts.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.