You need to scan the ABS module for codes and start there.
The cheapest option I know of is the app OBDFusion ($7-14) with the $14 Nissan enhanced diagnostic add on and a $10 wireless OBD scanner.
Then you can scan all the modules on your car's network, including the ABS module.
You can also view the individual wheel speeds in real time - very helpful!!
Here is a video that shows it on a G37: