Code P040, Power Steering Pressure Switch Open: Notes
WARNING: This page is about a different car, the 1995 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
This code test monitors Power Steering Pressure Switch (PSPS). When a load is placed on power steering, such as full lock, switch opens. Code P040 sets when vehicle speed is greater than 45 MPH and switch is open.