
Feeling good about having the FL5 about where I want it, I decided to start driving it a bit more. For a car I’ve owned since October 2023, having just crossed the 4500 mile threshold is a bit pathetic. Drive it and enjoy the thing, right? Sure, 94 octane gas is insanely priced, but still…
On a relatively nice day, I decided to take the FL5 to our local car wash. The last outing for it was a GTA rally, which took us over some back roads and even some dirt/gravel roads, so the rear bumper had some dust on it, and there were some decent mud splashes in the wheel wells, so I decided to take a run up and wash the car.
Not more than a mile from my house, the car suddenly threw a CEL on the dash, announcing that rev matching was disabled and the car would have reduced power. Sure enough, I noticed the rev matching, which I’ve grown to love, is no longer active.
Scanning the car with my Topdon scanner revealed the codes pictured above. I’d run this setup last year all season without a peep, so I was flummoxed as to what might have caused this. Got talking with a friend and remembered I’d added a TSP intake coupler at the end of last season (it really cleans up the look of the engine bay), but even with that change, I can’t imagine that would be enough to cause all these codes. The ‘Right Side BSI Radar Unit’ code is the real head scratcher – why is that squawking?

Two causes came to mind, and I’m not digging either possibility. First is that perhaps a rodent has chewed some wires and is causing some false positives? I had some traps set in our nicely appointed garage, and surprisingly caught a few mice and shrews in them throughout the winter. Foot note – I learned a lot about shrews from Reddit after catching one and trying to confirm it was a vole. Found an excellent thread on Reddit that explained the differences between mice, voles, and shrews. Did you know shrews have a poisonous bite? Now you do.
The other one, that scared me at the time, and had faded after I didn’t have issues, was my use of an ozone generator from Amazon to address a swamp smell my lovely crap dealership gave me as part of the dealer prep and delivery of the car. My guess is whoever the $15/hr prep guy was used some mildewed water left over from previous cars to wipe down or otherwise clean the interior. Didn’t notice it much when I picked up the car, but over the weeks I had it it become very noticeable, and was embarrassing when folks stuck their head in the car to check out the interior. I bombed the interior of the car for 30 minutes and then dealt with a lingering and overpowering ozone smell that lasted for nearly a year. Researching after the fact on ozone gave some troubling info about the potential for high concentrations of ozone to damage electronics and plastics. I held my breath and crossed my fingers, and last year the smell had finally dissipated, so I felt I had cross that threat threshold, but this incident had me guessing again whether it might be to blame. From further reading I’ve done on the subject, I’ve read that the level of exposure my car endured to rid of the swamp smell was nowhere near the levels and length of time needed to be at risk of damage. I’m trusting my research is correct.

Doing some research on these codes tells me that the P0420 is typically associated with down pipes, especially un-catted ones. My downpipe is a TSP catted pipe, valued for its ability to NOT trigger a code. The P16EB code is associated with an issue with the active exhaust valve that comes on the OEM exhaust. That whole exhaust was replaced by a Remark Ti exhaust, and thus the active valve hasn’t been connected in over a year. A quick search shows that FL5 owners typically don’t get a code from having the valve disconnected. I had previously pulled the fuse to keep the valve open for a more aggressive exhaust note on the stock exhaust (hint – it barely made a difference, and thus the beautiful sounding Remark exhaust), but just in case I’ve put the fuse back in for the non-existent valve.
Searching the internet about the B1E9A code was scary, as I got ZERO hits about it other than some Honda parts schematics showing the components involved. I think only one or two links were related to the FL5 platform – most were for Honda SUVs. The CivicXI.com forums are silent on references. Crickets has me pretty nervous.
I put a post up in the forums about the issues, but have only gotten a lone response that suggested clearing the codes and see if they come back. Probably a good suggestion as it is cheap and easy. If not, I’ll likely get a shop involved to see if they can find any issues that might explain the occurrence.































