Nav 9.1: Unable to read map data. Check if map DVD is correct. ('04 Prius)

There is a difference with the map DVD for the 04-05 Prius versus the 06-09 Prius. You probably purchased one for the later model Prius. In 06, Toyota changed the MFD to a higher resolution.

 

What generation is the DVD? You need a Gen4 v9.1 for the 04-05 prius (not a Gen5 v9.1 which is for the 2006 and on).

 

Many of the auctions contain the vehicle compatibility in the auction description. I'm guessing the auction you won did not. So I think you have two options:

First, if you know what vehicle (year and model) the DVD came from, you can find out what Gen Nav that vehicle used by searching the internet.

Second, I believe you can look at the "U" number on the DVD (under North America on the top right). I believe the "U34" is version 9.1 for Gen 5 systems and "U91" is version 9.1 for Gen 6 systems. I'm not sure what the "U" number is for version 9.1 for Gen 4 systems (it may be "U24"). By the time the 9.1 maps came out, there were no more Gen 4 systems in production, so it is probably quite rare to find a used Gen 4 version 9.1 DVD.

 

For the latest maps (version 10.1), it looks like the following numbers apply:

Gen 4: U25
Gen 5: U35
Gen 6: U92

I determined these numbers by reviewing a bunch of auctions on ebay and comparing the DVD "model numbers" in the photos with the auction description. So I'm not 100% sure they are correct, but they seem consistent through multiple sellers. A call to a Toyota parts department should be able to confirm.