Resetting maintenance indicator light after changing O2 sensors?

Hi:

I am going to change the O2 sensors on my 1998 TJ Wrangler Sport (6 cylinder, 4.0L). According to the Haynes manual, I need to reset the emissions maintenance indicator light. Here is the paragraph from Haynes manual:

"On 1991 and later models, the emissions maintenance indicator light can only be reset with a special tool available at most auto parts stores. After replacing the oxygen sensor, take the vehicle to a dealer service department or other properly equipped repair facility and have the light reset."

I looked up the factory service manual, and it did not mention any such indicator light. I wonder if anyone has heard such a light?

Thanks.