LogrobotLM

LogrobotLM — AI fault diagnosis for ABB · KUKA · FANUC robots. It reads your robot backup in your browser (never uploaded) and pinpoints the fault. Try it free →

FANUC Alarm SYST-166 — WARN TP intermittent communication error

Warning
Hardware
teach pendant
Controllers
R-30iA (this generation only)
FANUC class
WARN
Hardware family
FANUC teach pendant, main board, CMOS and controller battery alarms

FANUC SYST-166 (“WARN TP intermittent communication error”): Intermittent errors happened during the communication with the teach pendant. First check: Check that the teach pendant cable is working properly. Likely part: Teach pendant (Teach pendant).

Updated 2026-10-22 · LogrobotLM reference

Description

Intermittent errors happened during the communication with the teach pendant.

Remedy

Check that the teach pendant cable is working properly. Replace the cable if necessary. Check to determine if there is any source of electrical noise. Check that the teach pendant is working properly and replace the teach pendant if necessary.

Field diagnosis

Intermittent errors on the link with the teach pendant, without a stop.

What to check

  • Source of electrical noise, condition of the teach pendant, replacement if necessary.
  • Note: Precursor of SYST-165.

Part to check / replace

FANUC SYST-166 points to the hardware below — start here before ordering.

Tap a part for every code that points to it — and verify the exact variant for your controller before ordering.

Related codes

SYST-165PAUSE TP intermittent communication errorSYST-164WARN Teach Pendant communication errorSYST-168Robot is isolatedSYST-169WARN S/W Registration is temporary

Same hardware involved

SRVO-002Teach pendantSRVO-003Teach pendantSRVO-372Teach pendantSRVO-373Teach pendant

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →