Why is my engen light on?

Hi jayjay,

Since 1996 all cars sold in the US are required to support what's called On Board Diagnostics, or OBD-II, that specifies a way for the owner of the car to read out from the car's computer any fault information that's available. You do this by plugging in a code reader, also called a scanner, into the OBD-II connector located in the driver's seating area, usually under the dash.

Your car is continuously monitoring sensors all through the car, including the engine and transmission. When it detects a significant problem, by law it is required to turn on the check engine light to indicate that it has a Diagnostic Trouble Code (DTC) stored and that you as the owner need to read that code and take some action to repair whatever issue is being indicated.

So your car is seeing a problem and trying to tell you something's wrong. The next step for you is to scan your car's computer for any trouble codes that are present and based on which one or ones it is, you may need to fix something. Here in Oregon you cannot renew your car's license if the car has any trouble codes, so they have to be fixed to renew the plates.

You can buy an inexpensive Bluetooth device that plugs into your OBD-II port and connects to a (free) app on your phone in order to read those codes; some of them can be gotten for under $10 USD. Here in the US, virtually all auto parts stores will scan the codes in your car for free and give you a list.

Your mission, should you choose to accept it, is to get your codes scanned then come back here and update your question with the DTCs you found. In addition, tell us the year of your CX-3 and any other relevant information such as engine size, transmission type and submodel if any. Once we have that information we can then figure out what your car is trying to tell you and what you need to fix.