TL;DR: Honda won't fix my car so I made an app to keep gathering proof.
My 2018 Accord Hybrid appears to have the engine misfire problem Honda just put out a service bulletin for (https://www.kbb.com/car-news/honda-models-get-extended-warranty-over-head-gaskets/). Neither my dealer nor Honda will approve the repair unless two things are true: the code has to be showing when I bring it in, and the code has to survive turning the car off, waiting, and then turning it back on.
In the 5 years I've been dealing with the problem (random and infrequent loss of power at highway speeds, flashing check engine light, unable to maintain about 50 mph), we've gone from changing spark plugs, months at a time in the service center, to a partial teardown (at my expense) a diagnosis of a timing belt that may or may not have needed to be replaced, and finally 3 months this year so far in the service center.
Regarding the misfire code itself, at their instruction (service center and Honda corporate), we drove it to the service center while the problem was actively happening...on the highway, with check engine light flashing and engine very noticeably struggling. They captured the code both times. This past time they all told me that even though they captured it, they needed to be able to capture it a second time in order to approve a repair.
I'm at my wits end. In both cases, we've done what Honda themselves told us to do: bring the car in when it was actively flashing the check engine light. The first time around was pre service bulletin, but this time around the car was IN THE SHOP when the bulletin came out. I honestly don't know what practical avenues I have left to me, so in my frustration I started researching OBD scanners and what I could capture myself. All of this is to basically say that I built an iOS app to help me log and keep track of as much of what I can get from my car as possible. It's called Baseline OBD, and my overall goal was to keep it as minimal and clean as possible, while also being data-rich. It saves pending codes, misfires and freeze frames that would vanish after the next clean drive. I can export it all as a PDF, CSV files and raw records to hand to a mechanic.
I also included a beta idea I had to monitor the car across its own average (the Baseline title comes from this). It shows how close each of the car's own self-tests is to its limit. That includes the catalyst, oxygen sensor, fuel trim, warm-up, 12 V battery and misfires per cylinder. The idea is to catch a part wearing out before the check-engine light comes on. Like I said, this is very beta, so please take it as theoretical and not factual.
Anyway, my impotent frustration is your gain, because I'm releasing it totally free: https://apps.apple.com/us/app/baseline-obd/id6815648278
It only reads, never writes to the car or clears a code. There's no account and no tracking, and everything stays on your phone unless you export it. I've only tested it with the OBDLink CX adapter that I bought for myself, but feel free to try it out with your own and let me know the results (if you're willing). Please let me know if you have any issues or technical problems, solo coded and mostly solo tested.
P.S. My car is even still in the original warranty!
