LiftMaster · Garage Door Opener Serious

3-5 — LiftMaster 3-5 — Cable Tension Monitor (Jackshaft)

On wall-mount jackshaft openers, 3-5 means the Cable Tension Monitor tripped or is not detected (a slack/over-tension cable condition). It is not a Wi-Fi/myQ connectivity code — connectivity issues are shown by the LED/app, not a flash code. (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
liftmaster.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 at the opener.
  3. Have the cables/CTM serviced (cable work under tension is best left to a pro).

Why it happens

Typical signs: Wall-mount jackshaft opener · Door stops; flash code 3-5

  • Cable Tension Monitor tripped or not detected A slack or over-tension cable condition, or the CTM 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.

  • LiftMaster jackshaft cable tension monitor Common replacement
    Amazon →

More LiftMaster garage door opener codes

1-1 1-1 — Safety Sensor Obstructed, Misaligned, or Disconnected 1-2 1-2 — Safety sensor wire shorted or reversed 1-3 1-3 — Door control or wire issue 1-4 1-4 — Safety sensors misaligned 1-5 1-5 — No RPM Detected at Start of Movement 1-6 1-6 — Unexpected RPM After Stop at Open

All LiftMaster codes → All garage door opener codes →

Frequently asked questions

What does the 3-5 code mean on a LiftMaster garage door opener?

On wall-mount jackshaft openers, 3-5 means the Cable Tension Monitor tripped or is not detected (a slack/over-tension cable condition). It is not a Wi-Fi/myQ connectivity code — connectivity issues are shown by the LED/app, not a flash code. (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.)

What causes the 3-5 code on a LiftMaster garage door opener?

Cable Tension Monitor tripped or not detected: A slack or over-tension cable condition, or the CTM is disconnected.

Is it safe to keep using a LiftMaster garage door opener with a 3-5 error?

Limited use only. This is rated a serious-severity fault.

How do I fix 3-5 on a LiftMaster garage door opener?

Inspect the lift cables for slack, fraying, or coming off the drums. Check the Cable Tension Monitor connection at the opener. Have the cables/CTM serviced (cable work under tension is best left to a pro).

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: liftmaster.com.