sigs

Two days ago, I took a short (250 mi) road trip, all on major insterstate. About 1/3 of the way through, the Nav map ('05, DVD-based) started acting odd. Cursor became "jittery" and would bounce around a bit. A few miles later, it had the cursor moving parallel to my course, but about 1/4 mile off to the side of the Insterstate on the map. I thought that, since it was a cloudy, drizzly day, it was just having a little trouble picking up satellites, and there weren't enough turns in the road for the gyroscope to tell it to get back on track. Unfortunately, I didn't remember how to find the number of satellites it was picking up (via the "Info" button) and didn't have time to pull out the manual and search for it.

Then, it went completely wacky, and, by the time I had traveled another 20 miles, it showed the cursor about 50 miles off course, in the middle of nowhere. It also showed the car headed in the wrong direction, anywhere from 90-180 degrees off of my real direction. Not only did the map display show the wrong direction, but the compass display in the dash also showed the wrong direction of travel, typically by 180 degrees.

The rest of the PCM was working fine, but I thought this was one of those gremlins that might go away on engine shutdown and restart. No luck. Stopped for gas and gave it about 5 min off time. Restarted. Same problem.

Finally, after a couple of hours of this (by then, the cursor was 100 miles away and headed in the opposite direction), as I was entering the distant outskirts of another big metropolitan area, it "found itself," and has functioned perfectly (well, at least "as designed") ever since, including the trip home today, under similar weather conditions.

Since it cured itself, I fear that the dealer will be "unable to replicate." Anyone else run into this? Any tips for diagnosis or reset, should it happen again?

Shamus

This has happened to me a couple of times (04 cd based), No diagnosis or reset I am aware of. I can't recall if it happened before or after they replaced the PCM.

It happened to a lesser degree in my wifes acura, so I chalk it up to the sat reception

sigs

Thanks. I've also had it happen, to a much lesser degree, with every Nav system I've had (dating back to the old systems of about 10 years ago). That's why I wasn't concerned at first. But I've never had one show me being 100 miles away and headed in the opposite direction. If functioning correctly, the onboard compass, mileage indicators, and gyroscopes will do a remarkably good job (for a while) of keeping track of things (provided you aren't circling ramps in an indoor parking garage), even if you are picking up no satellites at all. This seems to have been a major computer glitch. It also is interesting that the in-dash compass, which the purchaser, of course, has to pay separately to have activated, simply takes the same feed as the Nav system. The reason I got it in the first place was as a back-up for when the Nav system died (as 2 of mine have done in the past). I guess my naivete knows no bonds. Wonder what kind of compass you get in a non-turbo, if you get the compass without the Nav system.

ChipAZ

Had a Mercedes that did that once. It had me in a different state. The Nav's are very similar right down to the sound of the voice. Never did it again as long as I had that car. Don't know what happened.