Key On, press and hold the menu button until "SERVICE MENU" appears in the screen. Release button. Scroll to diagnostics. Press select. Then scroll to switches, press select. Then follow the instructions sent via PM. If you want to check your shift solenoids anyway, go to diagnostics/trans and choose auto-test solenoids. If a solenoid is defective, "CHECK CODES" will appear on the screen. If there is no issue, screen will read PASSED KEY OFF.