LG · Oven Moderate

CF4 — Right-rear cooktop sensor open/short

Right Rear surface element sensor is open or shorted; control disables that zone.

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

How to fix it

  1. Disconnect power.
  2. Lift the cooktop, unplug the RR sensor, and measure resistance (~1090 Ω room temp).
  3. Replace sensor if open or shorted.
  4. Inspect/repair the harness; reseat the connector at the cooktop board.
  5. If the sensor and wiring pass, replace the cooktop control board.

Why it happens

Typical signs: CF4 on display · Right rear burner cold or runaway · Other zones may keep working

  • Failed RR zone thermistor Sensor open/short.
  • Harness damage under cooktop Chafing on chassis or heat from a neighboring element.
  • Loose cooktop board connector Plug not seated.
  • Cooktop control board fault Input circuit failed.

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) CF1 CF1 — Left-front cooktop sensor open/short CF2 CF2 — Left-rear cooktop sensor open/short CF3 CF3 — Right-front 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.