That does that (and its crap)
You probably need to replace the primary o2 sensor (I HIGHLY recommend against getting a bosch - denso is oem and is noy expensive @ sparkplugs.com)
The 2ndary, hook a multimeter to it and double check its conductivity - or just replace it too. You dont really need the 2ndary o2 - it doesnt send anything crucial back to the ecu, and will not cause limp mode. (Id still replace it, but if you dont feel like spending the cash, you can get away with not bothering for awhile, if at all)