My 2008 DTS developed a leak in the power steering system. Subsequently I found that the high pressure line had to be replaced. After the high pressure line was replaced the pump started to make a whining sound. Figuring that the pump had been under a lot of abuse I had the pump replaced with a rebuilt. The new rebuilt pump whined even worse. Another pump from the same distributor was installed and the whining was even worse. A rebuilt pump from AutoZone was installed and whining wasn't so bad. From time to time the service power steering system message comes on in my driver information display