How do you check idle speed module Mercedes c200?

To check the idle speed module on a Mercedes C200, start by ensuring the engine is at normal operating temperature. Use a diagnostic scanner to read any fault codes related to the idle control system, as these can provide insight into issues. Additionally, observe the idle speed through the scanner or by monitoring the tachometer; it should be within the specified range. If abnormalities are detected, inspect components like the idle air control valve and vacuum hoses for potential issues.