2000 Yukon XL, Oil changed less than 1000 miles ago, transmission just rebuilt, while driving home from tranny shop, the check engine oil level light came on and has stayed on. Oil level at full, per dip stick. What could be causing this?

2000 Yukon XL, Oil changed less than 1000 miles ago, transmission just rebuilt, while driving home from tranny shop, the check engine oil level light came on and has stayed on. Oil level at full, per dip stick. What could be causing this?

Since you just had the trans out, I would look at the possibilty of a damaged harness or oil level switch.
The switch is normally open, you can check the continuity of the switch to ground, if it is open, then the wiring might be the problem, if the switch is closed, then the switch is your problem