Cannot compute the route

[GaryXT]

Planned an 800 mile trip each way from San Antonio Texas to Springfield Missouri for Lamonster Garage rally. The planned route worked fine going there. When started the return, the Zumo XT said Cannot Compute the Route. Finally called customer service. He asked if I had the maps on a memory card, which I did. He said open the door on the card holder in the little slot and check the card, which I did. The card had slipped out of the the metal holder slightly. I reset the card and closed the door. Powered on and it worked! Problem solved. Thanks customer service. You did well.

[Peobody]

Do you have an explanation into why an un-seated SD card would affect route calculation? I would only expect it to affect an attempt to import a route or play music stored on the card. I ask because I encountered a "Cannot calculate route" on one of my daily routes on my last trip. Recreating it in Basecamp, including new waypoints, and then deleting the old and loading the new onto the XT worked. Luckily I had my laptop with me and could do that. My other 5 routes calculated fine so in my case I doubt is was an unseated card but am very curious about whether a unseated card alone could cause a route calculation issue.

[jfheath]

I don't have an answer for this. Clearly it worked and clearly tech support have come across it before - simply judging from the questions that were asked.

Typically, computers don't access data on storage devices every time they want it. Instead they copy a whole chunk of data into a cache memory so that it is readily available with faster access and avoids the relatively slow process of accessing the information. They assume that subsequent accesses to data are likely to data that is stored near to where the last data was stored.

So - just thinking out loud. The card was obviously in place when the map was read for the outward journey. Somewhere along the route maybe the card was displaced, but the relevant information was still in the cache, so it didn't need to access the card again. For the return journey - its actually the same map and the data already read would have been in the cache. But because it was a new route, the computer wouldn't have known that and would try to access the card to download a new section of map to the cache. And becasue the card had become diskodged on the outward journey, it couldn't

That card slot is VERY flimsy, and it isn't always easy to recognise if the metal slider has actually locked the card in place. The rubber door is very thick, and when replaced properly, it not only seals out the weather, but it presses down onto the card and slider, preventing it from moving.
It takes a little bit of effort to get the last bit of the rubber door to be pressed down into position. Its easy to think it is shut when the open end is still sticking up a bit - and therefore not pressing on the card.

Just a few thoughts. They sound feasible to me, sitting here on the other side of the atlantic.

[Peobody]

That makes sense if the map is on the card. @GaryXT, is that the case for you?

I don't have any experience with maps on the card. How common is that?

[GaryXT]

Thinking back on what could be the cause of the card becoming dislodged, I do remember that it slipped our of my hand and fell on a hard surface. I know... my bad. I think that might have dislodged it.

On my first call to support, the tech hit on the correct idea that certain maps were not being accessed. Two maps showed up as being on the until, but two were not, and would be necessary to do the calculations for the city streets. The ones which were not were CN North America NT All US, and CN North America NT All Mexico and Canada. He suggested that I re-download them, which led to another issue. I was at a motel, and their website requires that I agree to their terms when logging on to their WiFi. The Starbucks and McDonalds have the same policy. The XT has no ability to respond to that request, which I consider a short coming. When I made a second call, that tech went straight to the chip issue, which fixed the problem.

As an aside, after traveling 2000 miles, part of which was on very narrow, very curvy mountain roads, and getting within 5 miles of my house, the rear air suspension on my 2020 Can Am Spyder RTL, with 7500 miles on it, decided to go out. It was a very kidney shaking last five miles, but I was so very thankful that I was not stuck on one of those limited line of sight mountain curves.

[Peobody]

I would appreciate knowing whether those two missing maps were on the card so as to know whether an unseated card can cause a problem regardless of whether there is an attempt to access data on it.

As an aside, after traveling 2000 miles, part of which was on very narrow, very curvy mountain roads, and getting within 5 miles of my house, the rear air suspension on my 2020 Can Am Spyder RTL, with 7500 miles on it, decided to go out. It was a very kidney shaking last five miles, but I was so very thankful that I was not stuck on one of those limited line of sight mountain curves.

How fortunate that this happened so close to home but sheesh, a 2020 with only 7500 miles? Kudos for speaking so calmly about it.

[GaryXT]

The other features seemed to work ok as far as I tested. Did not do an extensive test, but could look at the map of the local area. From what I understand from them, those maps are necessary for the city part of the map and calculations. I may be wrong about that, but I believe it is correct.

Thanks for the compliment. Yes, I could have felt like yelling, but thankfulness overpowered that urge. I had prayed for traveling mercies, and if I was bound to have a breakdown, I could therefore see God's mercy in it happening so close to home. I could yell at the Spyder, but it has no ears. I could yell at Can-Am, but I doubt they read this thread. So, what's the use. My thought is to just evaluate the situation, find the best solution, work the solution, and then move on. The move on depends on what the solution was. Maybe I learned that from when I was an instructor pilot in the US Air Force in the supersonic T-38. IE, if there is an engine fire, does shutting down the engine solve the problem and put out the fire? Is so, where can I go to land and what kind of approach shall be necessary. Or if there is still a fire, try to get to a safe area and eject. If there is an emergency, and a person has to react by yelling and not giving first attention to the emergency, and loses sight of what needs to be done to handle the emergency, and perhaps lets a bad situation become worse, perhaps much worse and dying. Being able to pull off to the side of the road and stop and evaluate seems a luxury. Did not mean to get preachy, but it is a good practice to follow, I think.

[lkraus]

I'm wondering how the NT maps ended up on the SD card. Express usually puts them in internal memory unless it is already full. With all the standard North American maps in the 28 GB internal memory, my XT still has 12.7 GB free.