CEL came on yesterday and I am checking it today: the car drives just fine w/o any roughness. P1164 indicates a problem with primary(under the hood) air/fuel ratio sensor. The resistance across the black leads of the sensor pigtail is 0.1-0 .2 ohms. I then checked the #6 fuse in the pass. side kick panel...fuse is good. With the pigtail still disconnected and turning the ignition to ON I observed voltages of 2.75 v and 11.81v at the terminals which correspond to the black leads. I decided that it was only a sensor failure and that I needed a replacement. After doing several searches I am totally confused at to which part I need. I prefer a middle-priced Denso one if I could just figure out the right part #.

 

Your Accord 4 cylinder ULEV uses Honda part number 36531-PAA-307, which cross-references Denso part number 234-9025 for the air/fuel ratio sensor.