So I have been fighting an ABS issue on my equinox. It started about a month or so ago when the peddle would randomly flutter as if the abs was kicking in, and within a day it gave a code for the front left wheel sensor. So I went ahead and changed both front wheel hubs and with the sensor. Then the code traveled to the rear sensors. So I changed both of the rear hubs. No dice still throwing a code for the rear so next I changed the rear wiring harness. Now for some reason the code is back to the front left even though all 4 sensors have been replaced. Any ideas on where I should look next, or should I just take it to a dealer?

Thanks in advance for any help.