2014 5 Door ADV (SH-AWD ENT); KA 6AT w/ 118k miles.

Christmas tree problem. A number of telltales illuminate while driving. They all seem to be related to driver assistance (LDW, traction control, ABS).

Will self-resolve. Park it for a time, codes are gone.

If you drive some of the codes will even slowly disappear! Maybe. Maybe it's that they disappear during brief stops after the Christmas tree. In any case, if you park it for say :20 mins the codes are gone.

I was working off the principle that it was a low voltage situation, since these cars have quasi-smart alternators. So I have replaced battery/alt/batt sensor. Battery is 24F AGM. Alt is Denso. It needed all that stuff anyway, aside from the battery sensor (anyone want to buy a used battery sensor?)

Battery connections are great (I use dielectric grease), have checked both grounds I could find in the engine bay. I can't find more grounds because Honda doesn't publish the workshop manual in a manner I have decided fits my DIY weekend warrior approach.

No codes (aside from the temporary codes). Some of the boxes in the self-diagnosis (three button press hidden menu) are yellow, but it reports "no error". Sure would be nice if I had a table of what the self-diagnosis codes mean. I have cycled through all of them, and half of it is jibberish. It does show that the codes do not always occur all at the same time.
Interesting to note: when it has this problem, you have to double press on/off to shut it off. Also, the entry/exit goes into driving mode (not exit) when the door is open. The RFID key telltale also blinks at that time. Both fobs have new batteries and otherwise work fine.

Do not store fobs that near the vehicle. Also, it did not do this for years with the same parking pattern.

I don't have a perfect memory, but I think it started to happen right around the time of winter storm Uri, during which my battery died.

Also, both fans recently died (or the last one did anyway) and it overheated. My wife left it idling in a parking lot while running an errand. She shut it off pretty quick after overheat - no damage I can perceive. Lost about a quart of coolant. Head gasket is fine. I have since replaced both fans, although I got by for a time just cleaning the carbon out of them which surprised me. They were packed with soot from the brushes. I blew air in the weep hole and it looked like I was cleaning a DPF.

I have new fan relays on order in case that's it. Maybe they got hot while the fans were dying/dead.

It's got to be something! I am fine trying a few more things before I take it to the local independent Honda/Acura specialist.

 

Was just running through the TSBs again. 17-003 is interesting. I had that problem, and I see that I have the out-of-date HFL software. I will have to schedule a service to go get that updated and see if it makes a difference.

Do independent Honda shops have access to the same software? I might call them to ask.