Navigation Problems Persist - 2009 Mazda 6 Long-Term Road Test

2009 Mazda 6 Long-Term Road Test

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2009 Mazda 6: Navigation Problems Persist

October 19, 2009


Let's get down to brass tacks: The persistent navigation system problems we are having with our 2009 Mazda 6 have gone on far too long.

First reported back in April, we waited months for back-ordered parts to come in to fix a broken display screen. A new head unit was needed to remedy a mysterious red stripe that obscured the right-hand side of the display.

The parts eventually came in and we finally got the screen repaired in late August. But a short time later the "you are here" cursor started to wander -- first to Mexico, then out into the Pacific Ocean. At least one reader suspected the problem was a GPS error related to improper installation of the new part.

Circumstances prevented us from bringing it in straight away, but when we finally did we brought our Mazda 6 to a different dealer, in hopes of better service. They told us that all the system needed was a recalibration. "That will do it", they said. The work was done and the car was promptly returned to us the next day.

After a while it became obvious that this rush job was woefully insufficient. Our Mazda's nav system needs much more than a mere recalibration.

They should have have been able to tell that the GPS signal is not reaching the navi system, as evidenced by the lack of clock reading in the yellow circle, above. Without it's main guiding signal, the system resorts to groping its way along 100% of the time in "dead-reckoning" mode, a back-up mode intended to fill-in the momentary satellite blackouts that occur when the car is driven under trees or through tunnels.

DR uses steering, speed and acceleration sensors to approximate your direction changes, and this data is overlaid on top of the map. It doesn't know exactly where you are, but it can make a good guess if your starting point (and heading) was properly calibrated. It also makes the assumption that you're driving along roads that it knows.

This works fine for short hops in suburban areas. But if you drive miles and miles at a time in this mode, the errors pile up and the system loses it's way. Left unchecked, North becomes South and you wind up south of the border or far out to sea. It's no coincidence that the editors who noticed the biggest errors were the ones who went out on extended trips.

This weekend I drove to San Diego, 90 miles south. But I didn't notice that the cursor had started to diverge until I appraoched a meal stop in Irvine, about 1/3 of the way there. In the photo above the nav system thinks the car is on Von Karman Avenue. But I've put the manual cross-hairs on my true location on Jamboree Road, about 1/2 mile east. It's not a big offset at this point, but it played heck with my attempt to locate food.


After eating and restarting the car and zig-zagging out of the El Pollo Loco Parking lot, the system inexplicably lost track of north and south. Pretty soon it had me tracking north-northeast (as indicated by the the red triangle above) when I was in fact near the yellow circle, headed more or less south-southeast toward San Diego. At one point the difference between my actual and indicated positions grew to some 170 miles.

So much for the dealer's recalibration theory.

It turns out the recalibration procedure is in the manual, and it's pretty simple. I reset my position and direction this morning before heading to work. No dealer visit required.


As I suspected, this recalibration was just as ineffective. Within 30 miles the system started to develop a large-enough error that it could no longer estimate which of the closely-spaced roads it was travelling along. Here I'm driving on the 405 freeway, but the cursor is on a parallel path in a nearby Inglewood neighborhood.

Why can't the dealer service department recognize the obvious? No time signal means no GPS signal. And, more basic than that, a system with a functional GPS input knows that it's not miles away in another country or bobbing in the water like a buoy at sea. Errors like this should never develop where satellites are visible overhead.

C'mon service technicians and service writers, use your heads. We're bringing this thing back in once more to have the GPS signal restored, so you're getting another chance.

Dan Edmunds, Director of Vehicle Testing

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