Honeywell Home Security F38 Fix (Zone 38 Fault Guide)

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What This Error Means

F38 on a Honeywell Home security system basically means: Zone 38 Fault.

The panel thinks the device programmed as zone 38 (usually a door/window contact or motion detector) is not right — open, missing, tampered, or with a dead battery — so it nags, beeps, or refuses to arm.

Official Fix

Do it the manual way. You’re telling the panel, “Yes, zone 38 is really okay.”

  • Find out what “Zone 38” actually is.
    Check the zone list sticker inside the panel door, your install sheet, or the room labels on the keypad. Zone 38 will have a name like “BACK DOOR”, “KITCHEN WINDOW”, or “GARAGE MOTION”.
  • Visually check that device.
    Make sure the door/window is fully closed. On a contact, the magnet and sensor should be within about a quarter inch of each other and lined up. Nothing should be cracked, hanging loose, or half peeled off.
  • Close tamper covers properly.
    If it’s a motion or wireless contact, pop the cover off, then snap it back on firmly so the little tamper switch is pressed down. A loose cover = constant F38 fault.
  • Replace the sensor battery.
    Most Honeywell wireless sensors use a coin cell or a CR123A-style battery. Match the type and polarity printed inside the device. Swap the battery, wait 30–60 seconds, then close it up tight.
  • Wake the sensor up.
    Open and close the door/window once, or wave in front of the motion. This forces the sensor to talk to the panel again.
  • Clear the fault from the keypad.
    Disarm the system twice in a row with your normal code (CODE + OFF / 1 on most panels). Many Honeywell panels drop the F38 once they see the zone close properly.
  • If it’s wired, inspect the wiring.
    With power off, check that both wires are solidly landed under the zone screws at the panel and at the contact. No loose strands, no wire twisted together and taped, no obvious damage.
  • Power-cycle the system (if needed).
    If the zone looks perfect but F38 sticks: unplug the transformer, disconnect the backup battery, wait 30 seconds, reconnect battery, then plug the transformer back in. The fault list should refresh after reboot.
  • Still stuck?
    If F38 remains after all this, the official call is: replace the sensor on zone 38 or have a licensed alarm tech test the loop and RF receiver.

The Technician’s Trick

This is the “get the house armed tonight, fix it properly later” playbook. Use at your own risk — you’re reducing protection on that zone.

  • BYPASS zone 38 so the rest of the system works.
    On many Honeywell keypads: enter your 4‑digit code, then 6 (bypass), then 38. Confirm the keypad now shows “BYPASS 38” or similar. The beeping stops and you can arm, but whatever zone 38 is will not trigger the alarm.
  • Test if it’s really the sensor or panel voltage.
    If you’ve got multiple random F‑codes, pros go straight to the panel battery. A weak 12V backup battery makes wireless zones drop out. Swap in a fresh alarm battery, power‑cycle, and a lot of “mystery” F38 faults vanish.
  • Temporary magnet cheat for warped doors.
    If the door doesn’t shut close enough to the contact, technicians sometimes stack an extra magnet or a metal washer behind the existing magnet to bring it closer. Crude, but it’ll clear F38 until you can remount the hardware properly.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: Single F38 on one sensor, system under ~10–12 years old, everything else solid — just replace or re-mount that one device.
  • ⚠️ Debatable: Multiple random zone faults, panel over 12–15 years old, or you’re already eyeing smart security upgrades — fix F38 cheaply now, but start planning a full system refresh.
  • ❌ Replace: Panel is ancient, parts are hard to find, service calls cost more than a modern DIY system, or you’ve got several bad zones and a dead backup battery — put the money into a new system instead of chasing F-codes.

Parts You Might Need

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See also

Working through other devices throwing codes? These guides cover the rest of the house: