4wd

[907DAVE]

It means either you have a vacuum leak somewhere, or the vacuum pump is inop.

Check the vacuum lines that go to each of the spindles, they are prone to break the plastic fitting up on the bracket that holds them on the frame.

Also, check the fuses inside the cab, there is a 10 amp fuse that supplies power to the pump as well as a few other things, sorry cannot remember exactly what they were right now.