I agree that this is a great guide... But a tip from me is to check the cable on the
sensor before ordering a replacement.
You can do this by stripping a tiny amount of each of the four wires (near the actual
sensor) and then using a multimeter to test whether each cable is effective by touching one end on the bared wire and the other trying to find the connector pin on the socket that connects to the wiring harness.
I found a break in one on my rear
sensor and saved the hassle of trying to remove the
sensor (which on my 8yr old car was looking like it would have required removing the back box). I then felt the particular wire along it's length and found a 'flattened' section, bared the wire and crimped the cable together. Three weeks on and so far so good.
Edited by Mangham54, 22 September 2010 - 10:06 PM.