Stuck MPG indicator (2009 Impreza 2)

We’ve got a 2009 Impreza 2. The MPG indicator has been hanging out at 29 for a few months. Is this very sad? How do we get it “unstuck”?

Thanks much in advance


Maybe it isn’t really “stuck”.
If your driving patterns and driving style are very consistent, it is just possible that you are consistently averaging 29 mpg.

With my 2011 Outback 3.6R (my first car with a mpg readout on the dash), for awhile I thought that the indicator was not functioning properly, simply because it always seemed to read 22.5 mpg. However, then I focused on the fact that, as a retired person who doesn’t do much driving out of my home area, my driving patterns and driving style are extremely consistent.

When I did some driving in other areas, on different roads and at different speeds, I did see a change in the readout, averaging 29 mpg on long highway drives, and with the average reading plunging to 18 mpg after being stuck in a massive traffic jam for a few hours. But, when I stay in my usual environs, the average mpg reading always seems to hover at 22.5 mpg.

In order to test things out a bit, I suggest that you switch the readout from average mpg to “instant” mpg (or whatever they call a reading of your current mpg). When you accelerate away from a traffic light, you should see an “instant” reading of…maybe as little as 7 mpg. And, when coasting on the highway, you should see a reading of…perhaps 99 mpg (that’s the highest that my readout goes, apparently). If you see these variations on the “instant” setting, then that means the mpg function is working, and–more than likely–your average mpg readout is consistently the same because you consistently drive the same way, on the same roads.

When was the last time you “reset” the monitor? If you haven’t reset for a month or more the “history” is a large number and it will just stay on 29.

How would I go about this reset you mentioned?



You reset the monitor by re-setting the trip odometer.
Once you “zero-out” your trip odometer, the calculations begin anew.

I reset the “A” trip odometer at each fill-up in order to get the average mpg reading for the current tank of gas.
I leave the “B” trip odometer untouched, and that gives me the “historical” mpg average since I bought the car.

All of this is covered in the Owner’s Manual, so it sounds to me like you need to begin reading pertinent parts of that little book. You might be amazed at some of the things you learn about your car!

Every car with a monitor has a reset procedure. In my Toyota Sequoia the monitor is mounted on the roof above the rear view mirror. It has 4 buttons and you push and hold two buttons simultaneously for a few seconds. The mpg number changes from whatever (in your case 29) to 0. Then the mpg numbers change rapidly as you drive and eventually the average starts to settle down and change less frequently.

Every car is different so refer to your owner’s manual, or ask someone at a Subaru dealer.

Is this a mpg meter like on most BMW’s? Which is basically just a Vacuum gauge…and if you have that style…you may have something stuck in the vacuum hose… Just a thought.

If not I am assuming it is a digital gauge of some sort…I have only seen the BMW style…in well…BMW’s I love that gauge in the Beemer… Let us know… Maybe the only way to kick yours in the ass is a Batt disconnect for a little while…? But then again…that gauge gets its info from somewhere…a vacuum gauging device on the engine somewhere… Mite look that up on the inet in some Subie forums…