Hello. New Member here. I've just bought a new 2006 Outback 2.5 i Limited (first Subaru)and seem to be having a problem with the trip computer. When I have it on the setting that is supposed to display the current miles per gallon the reading fluctuates wildly. For example, it will jump from 13mpg to 29mpg to 70mpg to 99mpg to 50mpg back to 10mpg etc. I would expect it to fluctuate a bit based on my driving style but not this much. Furthermore, I know I'm not getting 99 mpg.

 

Has anyone else encountered this problem? Was it an easy fix? What do you think could be going on?

 

Any advice is appreciated.

You know that sounds reasonable. It is reading it in real time and has no buffer and no time delay. And actually at times you are getting 99mpg .. going down hill foot off the throttle.

 

 

Wait to hear from someone else with a trip puter, it may just need to have the ECU flashed, as that is where it is getting the information from. My gut feeling is that it is fine. What you want to read is avg MPG not real time MPG, which is what your seeing now

 

 

nipper

You know that sounds reasonable. It is reading it in real time and has no buffer and no time delay. And actually at times you are getting 99mpg .. going down hill foot off the throttle.

 

 

Wait to hear from someone else with a trip puter, it may just need to have the ECU flashed, as that is where it is getting the information from. My gut feeling is that it is fine. What you want to read is avg MPG not real time MPG, which is what your seeing now

 

 

nipper

 

Nipper is correct, you need to be on AVG and not CURRENT.

 

The AVG MPG will not start calculating until it has been running for over a mile.

 

Enjoy the new ride!

You know that sounds reasonable. It is reading it in real time and has no buffer and no time delay. And actually at times you are getting 99mpg .. going down hill foot off the throttle.

 

 

Wait to hear from someone else with a trip puter, it may just need to have the ECU flashed, as that is where it is getting the information from. My gut feeling is that it is fine. What you want to read is avg MPG not real time MPG, which is what your seeing now

 

 

nipper

 

Thanks for the information. What is the ECU, and what does it mean to get it flashed?

My 2005 Legacy is just the same way. In real-time mileage mode, you see the instantaneous average. My display updates about every second so I figure I am seeing the average of 1 second of distance traveled divided by one second of fuel consumption. As you are seeing, it can and will bounce around, especially as you go off throttle and are using almost no fuel in that one second interval.

 

The one thing I have noticed is that the Average fuel mileage rating is always optimistic, by 1-1.5 miles per gallon. I base this conclusion by dividing the trip mileage between tanks by the number of gallons put in and comparing the answer to the average shown in the trip computer. The trip computer is always high, which is not particularly surprising given the accuracies involved, but worth noting.

 

mikkl