ABS system

It will be on the left front wheel bolted on top of the spindle. If you need to replace the sensor then do both front sensors at the same time. The reason said is because of the sensor resistance. Since you will have a new sensor you could get a code for the right side sensor.

Also, do not overlook the reluctor ring on the rotors. Sometimes they will be installed crooked or accidentally knocked out of place when installing the grease seals, especially more true if you just had the front brakes serviced.