Will this sensor work if my check engine light is already on?

Yes. This sensor will read codes and help your engine computer correct the fuel mixture. Clear any existing codes with a scanner after installation, then run a drive cycle to verify the light clears.

Do I need any special tools or anti-seize compound to install this?

An oxygen sensor socket and ratchet are helpful but not required — a standard wrench works if you have clearance. Anti-seize is optional on the threads; the sensor will thread in and seal without it, though it makes future removal easier.

Can I install this myself or do I need a shop?

Installation takes 15 minutes if you have basic hand tools and access to the sensor location. Disconnect the negative battery terminal first, unplug the old sensor, thread in the new one, and reconnect the plug. No programming needed — it's a direct swap.