Service 4 wheel drive light on

Unfortunately this work "service" does not mean maintenance. It means there is an issue and it wants you to take it into the dealership or shop for service or repair.

We need to find out what the possible causes of this are by scanning for codes.

Here is a guide that will help with that:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

There are not always codes with this message but that is more rare. So let's start with what codes are there otherwise we are guessing.

If there are no codes then we need check the operation of the system. Does the 4WD system engage? Does the light flash? Does the light come on at all?

I attached some general info on the operation of the transfer case as well.

Depending on these results we will know what direction to go. Thanks