CF4 Moderate Moderate DIY

LG Oven CF4 — Right-rear cooktop sensor open/short

LG Oven · Error code CF4

What CF4 Means

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

Symptoms

  • CF4 on display
  • Right rear burner cold or runaway
  • Other zones may keep working

Common Causes

1
Failed RR zone thermistor

Sensor open/short.

2
Harness damage under cooktop

Chafing on chassis or heat from a neighboring element.

3
Loose cooktop board connector

Plug not seated.

4
Cooktop control board fault

Input circuit failed.

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.

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 cooktop surface sensor 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 F1 Range F1 — Upper Oven Thermistor Error F10 Range F10 — Door Locking System Failure

All LG codes → All oven codes →

Verified against manufacturer documentation: lg.com

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