Try cleaning your ps2 first, if that doesn't do it, then it could be the laser. (Just because it says "reading disk" doesn't mean that the laser works.)
If you think that the motor is bad then you will probably have to replace the entire CD drive. To test whether the motor works try putting a disk in and remembering what its orientation is (Example: the title is at the top or the title is sideways). After the ps2 gives the "read error" open the tray and see if the disk is in the exact same position. If it is, then it is possible that the motor is dead.
In short, I think that your motor is probably fine and your laser either needs cleaning or focused/replaced
Bosnoff
September 2007