P0141problem

There's 2 O2 sensors & that's referring to the rear one, in/after the cat.

I haven't had to do that yet on my 2003, but unfortunately I've heard you have to remove the passenger seat & look under the carpeting. Yup, the sensor wire goes thru the floorpan before you'll find a plug...

That's the code for the heater in that sensor. Get a multi-meter & unplug the sensor. There's 2 wires from the sensor itself that are the same color (black?). Measure resistance between them. It should be 10 to 40 ohms. If it's not, get yourself a new sensor. here it is on a 2004. yours is probably similar. http://sites.google.com/site/hondarepairsite/home/2004-honda-oxygen-sensor