LG · Oven Serious

F42 — Induction overvoltage / DC-link voltage error

The inverter board on an LG induction range has detected DC-link voltage outside the safe operating window. Cooktop output is shut down.

Keep using it?
Limited use only
DIY difficulty
Hard
Verified against
lgparts.com ↗

How to fix it

  1. Power off at the breaker for 60 seconds.
  2. Measure line voltage at the range terminal block — both legs to neutral should be ~120 V; leg-to-leg ~240 V. Out-of-spec voltage = utility/wiring issue first.
  3. Inspect the range terminal block and service cord for discoloration or loose lugs; retorque.
  4. If line voltage is correct and F42 persists, the inverter board is the likely failure — replace it.
  5. Do not keep cycling power into a hard F42; repeated surges can cascade-fail the main board.

Why it happens

Typical signs: F42 or F-42 on display · Cooktop zones go dead · Code may follow a brief power-line event (surge, brownout, generator switchover) · Smell of hot electronics in some failures

  • Incoming line voltage out of spec Utility surge, undersized generator, or shared neutral problem.
  • Failed inverter board input capacitors Bulk caps degraded; DC bus collapses or rings.
  • Failed inverter board IGBTs/control circuit Switching circuit cannot regulate the bus.
  • Loose/oxidized service connection Bad neutral or loose lug at the range terminal block.

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 induction inverter board 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 CF4 CF4 — Right-rear cooktop sensor open/short F1 Range F1 — Upper Oven Thermistor Error

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: lgparts.com.