ABS/TCS/TPM light can come on for failure of several sensors, but the most common is a malfunctioning wheel speed sensor. If they replace the hub (wheel speed sensor is integral to the hub) and got an error message they can very easily reset the DTC'*. If the lights are on there likely is still a problem with either the wheel speed sensor or the wiring. Have the dealership scan the vehicle for DTC'* (diagnostic trouble codes). That will tell you what the problem is.
As far as not having the proper scanning tool, you don't need a $5000 Tech II scanner to read and reset these codes. My $100 Actron scanner will do this.
2001 Bonneville SSEi (retired at 365,000 Kms.)
2014 Jeep Grand Cherokee Overland (yes, I know its not a GM)