# SIMATIC ET 200SP Distributed I/O system | | | | | | |---|---|---|---|---| |Document:|Distributed I/O system (11/2023, English)|||| |Type of topic:|Action| Replacing an I/O module #### Introduction When an I/O module is installed for the first time, a part of the coding element clicks into the BaseUnit. When you replace an I/O module with the same type of module, the correct coding element is already present in the BaseUnit. #### Requirement Refer to section [Application planning](https://support.industry.siemens.com/cs/mdm/58649293?c=158604469259&lc=en-de&dl=en). #### Replacing an I/O module You have already removed the I/O module. To replace an I/O module, follow these steps: 1. Remove the coding element (part) from the underside of the new I/O module. 2. Insert the new I/O module (same module type) into the BaseUnit until you hear it click into place. 3. Mark the new I/O module (labeling strip, equipment labeling plate). ---