Ran into the same problem a while ago. Didn't feel like plunking down the cash for a new OE HO2 sensor so I went with an inexpensive Bosch universal sensor. Ended up throwing a 43 that I couldn't get rid of. Trouble shot the damn thing and it ended up being the ECU itself. Somehow the Bosch sensor fried the damned thing.
I'd troubleshoot through the Helms first and if everything turns out tits, grab a spare ECU from someone and see if the code still sticks.