F38 Serious Hard — consider a tech

LG Oven F38 — Main-to-inverter communication error (induction models)

LG Oven · Error code F38

What F38 Means

On LG slide-in induction ranges, the main control board has lost serial communication with the cooktop inverter board. Cooktop and sometimes oven function are blocked.

Symptoms

  • F38 or F-38 on display
  • Induction cooktop dead or all zones show error
  • Oven may still bake on some models
  • Code appears within seconds of power-on

Common Causes

1
Loose comm harness between main board and inverter

Plug worked loose during transport or service.

2
Failed inverter board

Cooktop inverter MCU not transmitting.

3
Failed main control board

Main PCB cannot receive on the bus.

4
Damaged ground bond

Floating ground between modules corrupts the comm signal.

How to Fix It

  1. Power off at the breaker for 60 seconds and retry.
  2. If F38 returns, disconnect power and remove the cooktop service panel to access the inverter board.
  3. Reseat the comm harness at both the inverter and the main board.
  4. Inspect for crushed pins, burned connectors, or melted insulation near the inverter heatsinks.
  5. Verify the chassis ground strap is intact between modules.
  6. Induction inverter and main-board service typically needs a tech — replace the inverter first, then the main 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 induction cooktop inverter board View on Amazon→ Common replacement LG range main control board 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.