4

Plausibility Error in Sensor Circuit 1 (External/Internal)

Phoenix Contact · ib il safe 2-eco

What does 4 mean?

This fault indicates either an external plausibility error in sensor circuit 1 or that internal diagnostics are active, signaling an internal error. This state occurs when both sensor circuits 1 and 2 are active, the reset/start circuit is activated, and the segment circuit is open. It suggests an inconsistency in sensor input logic or an internal device malfunction affecting functional safety.

Common Causes

  • External plausibility error detected in sensor circuit 1
  • Internal diagnostics active, indicating an internal device issue

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    For external errors: Check the affected sensor circuit 1 for proper operation and signal integrity

  2. 2

    For internal errors: Perform a power down reset (switch off and then re-apply operating voltage)

  3. 3

    After addressing the error and performing any power down reset, conduct a subsequent function test

Browse all codes in this manual (8)
Verified technical data. Last updated: March 2026

Related Faults

Source: Phoenix Contact ib il safe 2-eco