[Blue Bowtie]

The '99 Regal should have had a DBC-VII system. I'm guessing you read a 1225 DTC. If you suspect the wire harness you can measure the wheel speed sensor output voltage at the controller harness just as you did at the wheel. If the signal is the same (or within a few mV) you can assume the harness is intact.

The controller (EBCM) can be replaced without replacing the entire system. The ECBM is not vehicle-specific, but IS system specific. In other words, if you have a four channel system without traction control, you will need a controller designed for that. If you have a three-channel system with an accelerometer input, you will need that specific controller. It the vehicle has an active brake/engine traction control or engine only traction control, you will need that type of module. The module communicates with the CAN bus, but shouldn't require any flash programming or set-up to install provided it is the correct type.