If You notice that the check engine light has turned on in Your 2018 GMC Terrain the first thing You should do is get off the road and park the vehicle somewhere safe as soon as possible. Prolonged driving can cause more damage to Your engine if the light has turned on. Once You are stopped You will want to use an OBD II scan tool to read the ECU for the code that was thrown that made the light come on. The most likely problem on a vehicle that new is that there is a problem with a loose gas cap. This will have a code for an EVAP system leak as the fuel tank does not have the right pressures in it.
Matthew J
July 16, 2020
If the check engine light on the 2018 gmcis on then you may have a couple off different issues. Realistically it can come on anytime the ecu detects and error and stores a trouble code. To check the code you will need to hook the vehicle up to a obd scanner and read the code. The light can also come on when you are approaching a service milestone. Issue that cause it can include a loose gas cap, leaks in the vacuum seals, engine misfires, low oil pressure, bad spark plugs, or really anything else. The check engine light is a catch all to alert you that something is wrong, but that something can cover nearly anything on the vehicle. Often it is minor, but it should not be ignored.
The Questions and Answers on this page are the statements and opinions of their respective authors and not VehicleHistory.com. VehicleHistory.com
does not research or authenticate any of the Answers provided.