Engine light on

You need to have the diagnostic fault codes read and recorded to know where to start. Those will indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. Those codes never say to replace a part or that one is bad, so do not let a parts salesman tell you that.

The people at many auto parts stores will read the fault codes for you for free. As for what is triggering the check engine light, here is the list of possibilities:

https://www.2carpros.com/trouble_codes/obd2