KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave ARCING INSIDE Error Fix: Arcing / Sparking Inside Cavity

Visible sparks during operation. Common causes: damaged waveguide cover (mica sheet) that absorbs grease splatter, metallic items inside, or peeling interior paint exposing bare metal. Replace the waveguide cover ($5-10 mica sheet). Clean the interior. Do not operate with visible arcing — it can damage the magnetron.

High severity2 fixes available✨ Free fix available

Quick Answer

Error ARCING INSIDE on the KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave means: Arcing / Sparking Inside Cavity. The top-ranked community fix is “Replace Damaged Waveguide Cover (Mica Sheet)” (medium difficulty, ~30 min, DIY cost: $10-$15). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · microwave

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many microwave repairs can be done safely at home, consider hiring a qualified technician if:

This is a high severity error — continued use may cause damage or a safety hazard
The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $120-$180.

Other KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave Error Codes

DOOR LATCH BROKEN

Door Latch / Handle Broken

2 fixes

Oven Cavity Thermistor Open/Shorted

2 fixes

Shortkey / Keypad Shorted

2 fixes

Touchpad / Keypad Open Circuit

2 fixes

Control Board Failure

2 fixes

FAN NOISY

OTR Exhaust Fan Noisy or Weak

2 fixes

LIGHT OUT

Interior Light Not Working

2 fixes

Sensor Error — Humidity Sensor

2 fixes

People Also Ask About KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave Error ARCING INSIDE

What does error code ARCING INSIDE mean on a KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave?

Error code ARCING INSIDE on the KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave means: Arcing / Sparking Inside Cavity. Visible sparks during operation. Common causes: damaged waveguide cover (mica sheet) that absorbs grease splatter, metallic items inside, or peeling interior paint exposing bare metal. Replace the waveguide cover ($5-10 mica sheet). Clean the interior. Do not operate with visible arcing — it can damage the magnetron.

How do I fix error code ARCING INSIDE on my KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave?

The most successful fix is "Replace Damaged Waveguide Cover (Mica Sheet)" (medium difficulty, ~30 minutes). Estimated DIY cost: $10-$15. HomeMD has 2 community-ranked fixes for this error.

Is error code ARCING INSIDE on a KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave serious?

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

Can I fix KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave error ARCING INSIDE myself?

Yes — the top-ranked community fix ("Replace Damaged Waveguide Cover (Mica Sheet)") is rated medium difficulty and takes about 30 minutes. Tools needed: T15 Torx screwdriver, Needle-nose pliers.

How much does it cost to repair KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave error ARCING INSIDE?

DIY cost: $10-$15. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave have?

The KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave has 8 other known error codes, including: DOOR LATCH BROKEN (Door Latch / Handle Broken), F1 (Oven Cavity Thermistor Open/Shorted), F2 (Shortkey / Keypad Shorted), F3 (Touchpad / Keypad Open Circuit), F5 (Control Board Failure), and 3 more.

What other error codes does the KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave have?

The KitchenAid KMHS120ESS 30 in. 1000-Watt Over-the-Range Microwave has 8 other known error codes:

DOOR LATCH BROKEN — Door Latch / Handle Broken (2 fixes)
F1 — Oven Cavity Thermistor Open/Shorted (2 fixes)
F2 — Shortkey / Keypad Shorted (2 fixes)
F3 — Touchpad / Keypad Open Circuit (2 fixes)
F5 — Control Board Failure (2 fixes)
FAN NOISY — OTR Exhaust Fan Noisy or Weak (2 fixes)
LIGHT OUT — Interior Light Not Working (2 fixes)
SE — Sensor Error — Humidity Sensor (2 fixes)

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