Most-Efficient Mazda CX-5 Has Least-Accurate Trip Computer

Cx5atgasstation

As part of our just-released $25,000 Compact SUV Shootout, we took the six contenders on an extended drive route of roughly 200 miles to test how efficient they truly were.

In the end, it wasn't a surprise that the highest EPA-rated vehicle won. The 2013 Mazda CX-5 is rated 26/32 mpg city/highway and 29 mpg combined. In our testing of mixed city and interstate roads that slightly favored highway speeds, the CX-5 returned 32.8 mpg. The next closest as well as only other compact SUV to best 30 mpg was the Honda CR-V at 30.3 mpg.

In the past we've often used the mileage computers as the basis of our scoring with the pump calculations as backup. We've written that today's modern trip computers can be more accurate than trying to do the math on a fill-up at the pump.

This time around we were glad we had the pump calculations to fall back on because while most trip computers were off by less than 1 mpg, the Mazda CX-5 was off by 2.7 mpg. That's nearly twice the number of the next worst offender, the Hyundai Tucson, which was off by 1.4 mpg.

$25,000 SUV Shootout Mileage Challenge

Before our trip we topped off all the vehicles at the same pump at a downtown Chicago gas station. After the trip we returned to the very same pump to fill up the cars.

And yes, all the trip computers showed more favorable mileage than the pump estimates.

We contacted Mazda about the discrepancy, and the automaker's representatives explained the 8% difference between readout and calculation is somewhat normal. During their own tests, they ran 24 identical mileage runs in California and used the same gas station; Mazda's average discrepancy was 3.2% versus our 8% difference. After four of their runs, Mazda encountered more severe differences between calculated mileage and the trip readout than we did.

Why? Mazda points to variations in the pump sensitivity and the tank size, but that doesn't explain why the other vehicles in our test weren't as severely impacted.

In case you're curious as to which crossover had the most accurate trip computer, it was our winner, the CR-V, which was off by .3 mpg.

Related
$25,000 Compact SUV Shootout
2013 Mazda CX-5 Review
SUV Buying Guide

Comments 

cody

Dave T.,

maybe i'm oversimplifying things, but i don't understand why these computers are not accurate. the computer knows exactly how far the vehicle has been driven and exactly how much fuel has been pumped into the engine to get it there. it seems like it should be simple math...am i missing something?

it seems like all of these optimistic fuel economy read outs from trip computers are just marketing fluff and should not be tolerated.

Gary

My 2005 Subaru Outback 4 cylinder non turbo automatic gets very disappointing mileage and the computer has always calculated mileage as 7/10ths of a mile per gallon better than it really gets as per pump calculation.
My 2000 Volvo V70, which gets substantially better mileage than the AWD Subaru, has a trip computer that is dead-on accurate.
I don't know how these automobile manufacturers get away with this.
My Outback doesn't come close to the EPA sticker.

Bob

Your results are interesting. After 3 tankfulls my Grand Touring CX-5 FWD is reading quite close to the pump calculation; 0.1 less 0.4 more and 0.4 more.

Danangme

My CX-5 Touring AWD usually shows 28-29 AVG MPG but when I do the math it is consistently 2 MPG lower even when I refill at the same pump at the same station.
Could be a class action suit in Mazda's future

Drew

I think the reason for the discrepancies in the CX-5 trip computer is the tire size. I have a feeling that Mazda calibrated the trip computer based on the 19" wheels that come with the top-of-the-line Grand Touring models. All other CX-5 trims (including the Touring model used in this comparison test) have 17" wheels. Two inches in wheel size is certainly a big difference, so I wouldn't be surprised if it is just the Sport and Touring models with the inaccurate trip computers. Bob's and Danagme's comments above seem to support this theory.

Jynk

Hi,

If you noticed you will always get better mileage from the computer than from your paper calculation and why is that? Not all gas is spent moving the car, were your AC on?? I noticed in my corolla that this have a huge impact on my calculations...

Drew I got the same computation and it's the 19 inch tires that are the common denominator. Well even with my computation, my (automatic) CX-5 17 inch tires are still giving me 33 mpg at 65 mph.

Jutta

Drew & Kevin - I just bought a Sport (17") and my MPG display showed 35.9 this morning, which cannot possibly be true on a new engine with only 700 miles on it, driving in the city during winter no less. So your 19" tire theory makes sense, but wouldn't that also throw the odometer and trip meter readings off too? (Since the meter thinks it's covering more ground than it actually is.)

And if that's true, wouldn't a manual calculation be just as wrong since the mileage is overstated? I'm taking mine on the highway this weekend and will check the odo/trip meters with the mile markers. Will post back with the results.

Well this is interesting. My trip meter/odometer is off - but it's *undercalculating* the mileage. This means I'm getting even BETTER mileage than the MPG display!

Over the weekend I did 4 separate calibrations with the highway mileage markers, over level terrain. My odometer counted 11.8 miles (vs 12 actual), 38.7 (vs 39), 32.9 (vs 33), and 84.2 (vs 85). It's undercalculating by about 1%.

With only 1100 miles on my odometer, my MPG calculator is now sitting steady at 36.3 and a manual calculation of my last fillup reveals I got 37.3 MPG - in city driving, on a new engine. Needless to say, I am pleased with my recent purchase.

James Lockwood

My trip computer on my 2013 Hyundai Elantra over states the mpg by 5 mpg! This is ridiculous and pure fraud! Do the math at the pump. Miles driven divided by gals to fill up. Outrageous ! If I hadn't put 2000 down they would have this car in their parking lot.

Lori

I bought the CX5 in July. I am only getting 19-21.9 mpg. I drive mostly city but some freeway. Anyone else getting such low miles? I am really disappointed! Also my Navigation and phone only work 1 out of
every 9 times i use it. I have taken it in, they downloaded files, the mechanic said it didn't "always recognize" voice commands, but the service manager said it worked for him. What do I do?

Mike

I bought the CX 5 recently as well. I do mostly city driving and I'm averaging 20-21 mpg. This is far from what I was told i would get. Also, I have been driving extra carefully (avoiding pushing the pedal down hard) to give it a fair test. The number seemingly keeps dipping.

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