Chamberlain · Garage Door Opener Serious

3-5 — Chamberlain 3-5 — Cable Tension Monitor

3-5 means the Cable Tension Monitor tripped or is not detected (a cable slack/tension condition). It is not a travel-module/encoder position-loss fault. (Diagnostic meaning corrected against the official Chamberlain Group / LiftMaster Security+ 2.0 chart; flash-code meanings can vary by opener family — confirm for your exact model.)

Keep using it?
Limited use only
DIY difficulty
Moderate
Verified against
chamberlain.com ↗

How to fix it

  1. Inspect the lift cables for slack, fraying, or coming off the drums.
  2. Check the Cable Tension Monitor connection; have cables serviced by a pro.

Why it happens

Typical signs: Door stops; flash code 3-5

  • Cable Tension Monitor tripped or not detected A cable slack/tension condition, or the monitor is disconnected.

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.

  • Chamberlain garage opener cable tension monitor Common replacement
    Amazon →

More Chamberlain garage door opener codes

1-1 1-1 — Safety Sensors Obstructed/Misaligned/Disconnected 1-2 1-2 — Safety Sensor Wires Shorted or Reversed 1-3 1-3 — Door control wire issue / lock button stuck 1-4 1-4 — Safety sensors misaligned or obstructed 1-5 1-5 — Motor Drive / No RPM at Start of Movement 1-6 1-6 — Unexpected RPM After Stop at Open Position

All Chamberlain codes → All garage door opener 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: chamberlain.com.