LG · Oven Moderate

CF1 — Left-front cooktop sensor open/short

On combination ranges, CF1 indicates the Left Front surface element temperature sensor is reading open or short. The cooktop disables that zone (and on induction may disable the whole top).

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
lg.com ↗

How to fix it

  1. Power down at the breaker.
  2. Remove the cooktop assembly to access the LF zone sensor.
  3. Disconnect the sensor and measure resistance at room temperature — typical ~1090 Ω. Open or short = replace.
  4. Inspect the harness end-to-end for pinch/burn damage.
  5. Reseat the cooktop board connector.
  6. If sensor and wiring are good, replace the cooktop control board.

Why it happens

Typical signs: CF1 on display · Left front burner will not heat or behaves erratically · Other zones may still work

  • Failed LF zone sensor Thermistor on the element/coil failed.
  • Pinched or burned harness Sensor pair under the cooktop is chafed against the chassis.
  • Loose connector at the cooktop board Vibration backed off the plug.
  • Cooktop control board sensor input failed Board reads open/short with sensor isolated.

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 cooktop surface sensor Common replacement
    Amazon →

More LG oven codes

5b 5b — Sabbath Mode active (not a fault) 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 F10 Range F10 — Door Locking System Failure

All LG codes → All oven codes →

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.