Will this trigger a check engine light if my old sensor failed?

Once you install the new sensor and clear the fault code with a diagnostic scanner, the light should stay off. If it comes back immediately, the sensor wire or connector may have damage — inspect the harness before troubleshooting further.

Do I need to do anything special when removing the old sensor?

Disconnect the battery first to avoid any electrical feedback. The sensor unplugs from the harness and unbolts from the rotor assembly — standard hand tools handle both. Once it's out, inspect the mounting point and connector for corrosion or bent pins before installing the replacement.

Can I install just the rear sensor, or do I need to replace both sides?

You can replace one side if only that sensor has failed. ABS systems work side-to-side, but a single faulty sensor won't prevent the other from functioning. If both are aging, replacing them together is smart preventive maintenance.