I know this is an old thread but I thought I’d reply in case anyone else stumbles across the topic and needs some help! I have a 2006 Honda CR-V and live in California. I recently went to smog it and to my surprise it failed due to an incomplete catalyst monitor. This was especially strange because the last time the battery was disconnected was like 1200 miles and a couple months ago! The smog shop turned me away and only suggested driving it a lot to get the test to run. I looked up the drive cycle and did it once or twice a day for a week but it still showed incomplete catalyst every time I plugged in the OBDII. The car ran great and had no codes.
I do all my own car work since I’m the most capable and trustworthy guy I know, so I decided it would be worth the money to start by replacing my coolant temp sensors in case they weren’t accurate enough to initialize the temp criteria for the ecu to run the test.
I replaced them both, one is hidden in the block next to the air box which needed to be removed to access it. The other is also known as a “fan switch” and is in the bottom of the radiator near the middle. You have to drain your coolant to do the fan switch but the whole job was very easy in general.
The very next morning I ran the drive cycle and it completed the catalyst test, 0 codes, good to go. Total cost under $100. I got Duralast sensors from autozone for around $30 each plus a jug of blue coolant because I didn’t want to wait for original Honda sensors from Hondapartsnow.
Glad I went through this because if not, I might not have found Ericthecarguy! Appreciate your videos and info, very good stuff!