I do volunteer work At youth Crisis center here in CA and someone donated this 2008 Azera to us a year ago. Recently the ABS and ESC light comes on and keep getting error code P0501 which says it is a speed sensor. so trying to save the center a little money and trouble shoot and repair myself. We had a different error code (722) a month ago and replaced the input and output transmission sensor. My question is where is this speed sensor located and is there a way to scan for the problem in case in ABS sensor. Dealer wants 200 dollars to diagnose plus whatever the part may be and they just don't have that kind of money . Any suggestions are very appreciated Thank You in Advance.