Tricky ABS/DSC/4x4 Inactive message

[Ziad]

Alrighty, you could find douzens of posts that has to do with the abs/dsc/4x4 inactive message. Very typical, speed sensor or abs module kinda thing.

On my X, here's what i've done:

1. Replaced ABS module
Lights came on again. GT1 says it's the front left speed sensor. The light comes on after about half a mile or so. Usually when stopping at the first stop sign and drive again.

2. Replaced speed sensor with a brand new one
lights came on immediately!! not even half a mile, as soon as I started the car, lights came on.

3. Got my old speed sensor back in after bit of cleaning
it worked perfect...for about a month then it came back

the speed sensor socket is a bit rusted. Should I just keep on cleaning or is there something i should be addressing here?

Thanks!