Siemens S5-115U Error FEST: Error in the CPU self-test routine

Siemens S5-115U Programmable Controller · taken from the manufacturer’s manual, pages cited

Error codeFEST

Error in the CPU self-test routine indicating a hardware fault requiring CPU replacement. The manual's first action is: “Replace the CPU.”

Model
Siemens S5-115U
Display shows
Error in the CPU self-test routine (FEST)
Type
Error code
Source
Manual p. 138

What FEST means

Error in the CPU self-test routine p. 138

Common causes

  • There is an error in the self-test routine of the CPU. p. 138
  • Error in the CPU self-test routine p. 138

What to do

  1. Replace the CPU. p. 138

Before you service the product, read the safety instructions in the manual p. 414.

If FEST is still not resolved

The manual gives no further instruction for this code. Open the code table in the PDF or contact Siemens service.

Open the manual at page 138 All S5-115U error codes Manual details & download

This page summarises what the manufacturer’s manual says about FEST; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with Siemens. Found a mistake? Report an error.