That would depend on what system you are using to automatically pay your taxes. You don't say in your question, so no one can answer it for you. :-)
If you are using the government's EFTPS site to schedule payments, you definitely should contact them and you should have letters from the EFTPS and your online account there that will remind you what your PIN/code are.
I hesitate to say it, but in case you forgot: If you set up your bank account or Credit Card to autopay, then you should look at that because sometimes in my experience they update their service and you have to confirm or sign in again etc.