awd disable light stays on on 2006 Buick Rendezvous

AWD light stays on, I was told to replace clutch pump oil flow check valve. The part is expensive. Has anyone had this occur.

Asked by for the 2006 Buick Rendezvous
wow, never heard of that one.
I would look at the tires first for correct depth. if you have one new one, the light will come on and disable the system because of different roll speeds.
the other cause would be an abs problem that will disable the awd.

check the basics first before looking for anything else.

1 more answer , 2 more comments
You need a new flow valve. To change one, you need to locate the old one, which is located in front/bottom of the rear differential. Put a drain pan under the rear differential, disconnect the electrical connector and remove two screws and slide out. The fluid will come out and drain into the pan. Reinstall with a new flow valve. You have to add new versatrak fluid to the differential in the fill plug until it flows out. The flow valve was $400 and the versatrak fluid was $100 at the dealership for four pints. It fixed the AWD disable problem.
changed fluid,light comes on once in a while when putting it in reverse