Can anyone enlighten me on how the trip computer computes avg. mileage. I assumed that the mileage to the right of the trip odo. was the average mileage accrued over that trip. I have approx. 3500 miles on the car, and have not reset trip 1 since purchase, so it is a running avg of FE over the life of the car. It is at approx 38 mpg, since we have experience terrible weather since the purchase of the car..... and other reasons (spouse). I went on a 120 mile trip to my parents last weekend and got 48 mpg over that trip (figured with trip computer 2) Somehow over that trip, trip computer 1 eased from 38 mpg to 47 mpg over that trip. How could 120 miles at 48 mpg make the overall avg. for the life of the car jump so drastically? Is there a programming error??? Strangely the mileage on trip 1 is now back to around 38 after some shorter trips this week???

Some 06 owners have reported a problem with the average mileage. Check this thread for more details.

Basically your Trip A is completely useless since it has always only shown the average mileage over the last 1-63 miles. It resets internally after every 100 km (62 miles), but it won't reset the display until 1-2 miles after. So it resets at 63, 125, 187, 249, 311, 373, etc.

I know there have been several cars that have had the issue with the AVG MPG resetting. I haven't had this problem, but today I noticed something funny. The whole way to work today my average flucuated between 49 and 51 MPG. When I got in my car today to go home from work my readout showed 50.4 MPG. The engine was cold ofcourse, but instantly as soon as I began to drive my mileage dropped to 35 MPG. I didn't do anything out of the ordinary. In the morning it dropped when I first started to drive but it only dropped like 3-4 MPG but quickly returned to the previous reading after warming up and it was much colder outside this morning than this afternoon. By the end of my trip this afternoon I managed to get my mileage back up to 49 MPG. I just found that odd to do that all of the sudden and stay much lower for much longer. My trip A was well above the infamous 62-63 Mile mark.

Just clarifying that the mpg will reset around trip mileage of 62.5, 125, 187.5, etc., Not sure what you meant by "well above...mark". It only records the last 62.5 mile "segment".

Jesse

Never seen my 06 HCH do that. It always seems "normal" to me. Only time it is a bit strange is when I reset it when refueling. Then of course it starts at 0 and goes up quickly to the mid to upper 40's. Thats evey 400-450 miles.

Regards,

Bob

Yeah the bug isn't on all cars, just some of them.

I haven't noticed that our trip (neither A nor B) really fluctuates that much. I have noticed though that the MPG's shown are off from what I calculate manually after filling up. For instance this last tank, trip showed 46.7 MPG, when calculating it by hand I really averaged 53.1 MPG. I guess this is due to the programming problem that everyone it talking about and how the trip computer only calculates for the last 63 miles travelled.....?

Apparently, not every vehicle has that problem which is strange.

'06 HCH II w/Navi
'01 S2000

My wife and I reset Trip A yesterday to test this bug. This morning we carefully watched as the mileage went from 61 to 64 miles. No abrupt change noted. Just the normal expected .1 mpg changes.

Will watch this evening as we pass thru the 124 to 126 mile mark.

Ron in SoCal

Saving the Dinosaurs . . .