2007 FLHX - I've had the PO152 code come up in the past, but have cleared the code and moved on. The bike is completely stock, without a tuner. I've replaced the TPS (throttle position sensor), cleaned the Idle Control Valve port and replaced both fuel injector Electrical Connectors. I purchased the bike used 2 years ago, it has never been to the dealer or a tuner under my ownership. I'm not sure when the ECM was flashed / updated last. I would rather NOT let the dealer touch it unless I absolutely HAD to. I'm still chasing a periodic LOW IDLE condition that I am hoping is related to this O2 Sensor fault.
My question is, should I replace the rear O2 Sensor, or both O2 sensors? Should I try and clean my existing (potentially failing) O2 Sensor’s head? What’s the best source for O2’s?

 

I replaced both couple years ago partially cause oem was not that expensive.

 

the sensor can fail from additives in the gas, or silicone sealer used on a gasket on the intake or
soot build up

you could try to clean it with a wire brush.

I'd unplug and replug it.

see if it comes back with a cleaned up electrical connection

I haven't had to yet on the 2009, but boschs for the cars ran about $40

if the o2 sensor is sending low voltage, the ecm would respond by getting rich here and there.

But I am fairly sure that the idle and WOT use canned maps and do not use o2 sensor input- so your idle is likely unrelated to the o2 sensor

mike