Following up on my earlier post, a reader responded saying she has a 4-button remote with FCC ID MYT3X6898B on the back rather than a 3-button remote.
This is certainly possible. Some GM SUVs that used these systems had a rear function — hatch glass or liftgate — that was operable with the fourth button on the remote. This rear function will only be available on vehicles that had it originally . . . you cannot “activate” this option simply by buying a 4-button remote.
The parts are interchangeable, but the 3-button keyfob, being more widely used and more widely available, is much cheaper. To see both parts and get the sale price on the 3-button remote, go to: