Hi @ryanklothk25632
Find out what DTC (diagnostic troubleshooting code) has been logged, by connecting an appropriate [https://www.klavkarr.com/vehicle-list-compatible-obd2/citroen|scantool] (supplier example only) to the vehicle's [https://www.klavkarr.com/location-plug-connector-obd/Citroen-C3-2|OBDII port]
This is the quickest and surest way to find out what's causing the check engine light to come on.