phenomenal.kat

2019 TLX V6 A-Spec (not the AWD)

On a long trip, right after filling my tank and maybe an hour later using my parking brake, I got two errors that showed up at the same time while I was driving - P0441 (which I've learned is EVAP System Leak Detected) and U0401-68, Parking Brake System. From what I've been able to find out on the P0441, it looks like it's a possible failed purge control valve. However, the only thread I could find on the forums about the U0401-68 error was one person who has a 2017 MDX and had this error, and lo and behold the dealership told them it was a failed purge control valve.

My first question is: what in the world does the parking brake have to do with the emissions system? this just strikes me as hilarious, but I'm sure there's an explanation!
My second question is: could using 87 gas have caused the error code? My husband said his mind was elsewhere and accidentally filled the tank with regular about 2 tanks previous to this trip. I did notice a significant difference in the mpg, but other than that, I didn't notice anything off.

Thanks for your help!

Jim2301

I hope and pray that EVERYONE on this site reads and digests this thread...

Instead of the simple "I got this code, and don't know what to do" type of thread starter that we too often see, this contributor:

1) Told us the year, model, engine, etc. of the vehicle
2) Outlined the issue that occurred AND conditions observed
3) Did substantial research on her own to try to solve (including the near-term history i.e. "87 octane fill")

The situation/cause is beyond my now obsolete knowledge of the newer fuel delivery configurations, but ,my experience is that there are several very well versed Honda/Acura experts prowling this site that may be able to solve this one. Looking forward to seeing posts from our experts that, hopefully, will shed some light on the malfunction.

AND "Well done" to the thread starter for the well thought out and presented description!!

18TLXAspec

So, there are a few things U0401-68 could be related to, but since you mention the parking brake system I looked at that. For that, the diagnostic procedures have you follow PGM-FI system troubleshooting if the code isn't intermittent. So, that's likely where the connection between the two exists. I doubt that 87 octane alone would be the culprit, but poor quality, or contaminated, gas would seem to be a more likely culprit. Since you noticed a significant difference in mpg I would lean towards that.

sokolich

I just had this corrected a week or so ago. My 2019 threw the emissions code and parking brake code. I took it in and they diagnosed it as an EVAP solenoid. Replaced the EVAP and said it should be ok., but they did detect a small EVAP leak but to drive it and see if it came back. One week later both errors came back. I called and was able to get it back in. They then changed the purge valve and that didn't fix it. Finally, the service tech called me and said that they incorrectly diagnosed the issue wrong. It wasn't the EVAP or purge valve. It was the fuel filler neck. It was leaking fumes. Replace that and it has been ok for the last two weeks. I was out of warranty on the emissions but I have an extended warranty. The dealership was able to get my warranty company to cover it. Total was $258 for the EVAP at the first visit. I paid that out of pocket.
I asked them why the parking brake code would have anything to do with the emissions and they told me that in the wiring/computer they two are synced together for the code. Go figure.
Hope this helps!
Scott