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ABB Error 34256 — Rectifier temperature warning

Warning

ABB 34256 (“Rectifier temperature warning”): Rectifier temperature warning: the rectifier of the drive module is approaching an excessively high temperature level, without having yet reached the cut-off threshold. Likely part: Redresseur / Ventilation (rectifier / cooling).

Updated 2026-10-22 · LogrobotLM reference

What it means

Rectifier temperature warning: the rectifier of the drive module is approaching an excessively high temperature level, without having yet reached the cut-off threshold.

What to check

  • Clean or replace the air filters and check that the airflow to the rectifier is not obstructed.
  • Check the operation of the cabinet fans.
  • Check the ambient temperature and the cycle load.
  • Deal with it before the blocking fault appears.
  • Note: Warning stage preceding the blocking error 34255. Older equivalent: “593 TEMP. REDRESSEUR” (S2/S3).

Part to check / replace

ABB 34256 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

34100Drive system fault34200Axis Computer / Drive Units fault34201Drive Unit fault

Same hardware involved

34255Redresseur / Ventilation

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 →