O2 sensor went bad on my '01 HX. Replaced with Bosch universal but it doesn't seem to work, still get check engine light with code P1166 which in the book talks about the heater. (?!) I've found a place that has a Denso OEM sensor but it is $192. Does anyone know anything about this? I've been wrestling with this for 2 weeks now.

 

maybe the "power" or "signal" lead to the o2 sensor is bad??

It could be the wiring and not the sensor itself: In order for the o2 sensor to work it needs to be warmed up... maybe it doesnt have power to warm up or the signal isnt reaching the sensor to make it warm up... try that out.

 

yeah, i had a similar problem and it was broken wiring.