Ok, just had the 'Maru in this morning to do the fix, and though the Honda tech bulliten says 0.6 hours (36min), it took them (Immke Northwest) a little under two hours to complete. I don't mind that too much, especially considering mine was the first one they had in for this so far. Just a 'heads up' to everyone that it does take a bit longer than Honda's lab would suggest Now for the thinking cap part:

I went in with the following numbers:
Lifetime Odo: 14285
Trip A: 18mi @ 38mpg (I filled up Friday evening)
Trip B: 5430mi @ ~49mpg (This keeps track of oil life, currently 40%)

As I pulled out, I was at:
Trip A: 18mi @ 27mpg (to be expected from a dealership at such a low trip distance)
Trip B: 5430mi @ 31mpg (!!!!!!!! WTF?????)

So, we have the A odo behaving as you'd think, but I don't see any way possible for the B odo to have crashed like that, especially with 5k miles on it already.

The plot thickens... Parking at my apartment:
Trip A: 22.7mi @ 40.6mpg (**** I'm good)
Trip B: 5435mi @ 40.6mpg (Say what???)

It's almost as if the B odo is now mirroring the trip A odo, despite the fact that it's got over 200x the miles on it.

The question.... has anybody else noticed (or thought to look for) this happening? I plan on keeping my eye on both for the next tank or two and seeing what happens.

 

Sounds like a classic case of the 62/63mi/100Km bug, whichever you choose to call it. Since you've been a member here since April of last year, I assume you bought the car around that timeframe? Did you get a letter explaining the fix, or is this not "the bug"?

If you don't know about the bug, you can read about it ad-nauseum. Bottom line, if you have it, is take it to the dealer. They will replace your instrument panel.
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Not the mileage bug. I picked up the car in mid-March, and it's never exhibited even the slightest hint of having it.

 

Well, yes of course. If I'd thought about it a little more, it changed by adding less than a mile at the dealer, so the bug would be very unlikely.

I have a bead on what's going on, though. My car is at the dealership right now. They have it to "fix" the "spoiler rubbing paint off the trunk" problem (more on that in a later post). They called me yesterday and told me it was ready to go, and mentioned that they had also fixed the battery cap problem. I picked up the keys, but didn't have another driver, so the car is still sitting in the dealer's lot.

I drove over there this morning to see what my mpg readouts were. When I dropped the car off, I reset the B trip OD. I didn't record the A trip OD, but I know that I was getting somewhere in the low 40's on this tank.

Right now, sitting in the dealer's lot, trip A reads 197.1 miles, 7.3 mpg. Trip B reads 1.9 miles, 7.3 mpg. So the mpg reading definitely zero'd out when they disconnected the battery. Apparently, this data must be stored in volatile memory in the computer, which resets when main battery power is removed. It would be interesting to see if the same thing happens when the 12 volt batter is disconnected (I doubt it).

Chris, that is why your A and B are reading exactly the same - they were reset at the same time.

btw, the 7.3 mpg doesn't surprise me - it has been in the single digits here temperature-wise, and the dealer likely started it cold, drove it to the body shop, worked on the spoiler, started it cold again, drove it back to the main garage, fixed the battery cap problem, started it cold, took it out for a short test drive... VERY poor driving conditions.

So, beware all - when you take your car in to get the battery cap problem fixed, your mpg readings will reset!

 

Hmm... certainly a plausible theory. Seems rather odd to keep the tank mpg data in a different register than the tank mileage, and that it would be volatile while the mile data isn't. But it does fit the facts as we see them so far. Wonder if the datasheets msantos has might shed light on this.

 

I had a similar thing happen with Trip B -
Driving into the lot = Trip A was the same as driving off after the cap replacement.

Trip B - driving into the lot, mpg reading was 44

Driving off the lot, it was 1

 

me too. Same thing. Only I was using trip A to track the car's lifetime mpg. And now it's gone.

 

When I disconnected my 12v battery to install my foglights, both the mileages did the same thing , they reset to zero, and until my first reset of trip A, they mirrored each other.
Also interesting, when I started the car the IMA battery gauge was at zero, had to hold the throttle 3000-4000 RPM for about 5 minutes to get at least 3 bars, when I left for work a couple hours later, it readjusted at the first light, all 6 bars came on.... Pretty wierd

 

come on, there must be a way to keep the gauges from resetting when the battery is disconnected.

 

A trick that I use to keep the radio, etc. from loosing their memory contents, is to wire a 9V battery to a cigarette lighter adapter plug, and plugging it into the car.

This way I can disconnect the main battery, and the 9V battery will provide enough juice for 3-4 hours to keep the other things from loosing their minds.

Make sure that the dome lights, etc. are turned off, or the 9V will drain quickly. Another option is to use a battery maintainer instead of a 9V battery.

This is an old mechanic trick.