The wonders of the interweb! This is a post by Richard Hamilton a really knowledgable chap on all this stuff, I quote him:-
This is a summary of the updates available for PCM2.1 systems fitted to MY2005 and MY2006 9x7 vehicles, which are required to run the latest maps (currently 08.2009 – MY2010).
First, determine the current (Actual) software versions for the PCM and Amplifier.
Press MAIN + TRIP together
Scroll down to PCM and select
Make a note of PCM Actual Version
Go back & scroll down & select Amplifier
Make a note of Amplifier Actual Version. If your car does not have an amplifier, the option will not be there.
There are 4 levels of PCM software version:
04035xxx – Standard Production Status (Up to Week #42, 2004)
04202xxx – Model Level A (from Week #42, 2004 to Week #16, 2005)
05024xxx – Model Level B (from Week #16, 2005 to Week #22, 2006)
05395xxx – Model Level C (from Week #22, 2006 onwards)
There are several early versions of the Bose amplifier, and it has been found (the hard way) that updating these using the Level A update CD can cause the amplifier to fail completely, and require replacement.
If Amplifier Actual Version is less than 00017500 (ie 00016401) then do not attempt to update the system using an update CD. SOME of these early amplifiers can be updated using a PIWIS tester, but others require replacement. I would suggest contacting a Porsche Centre to determine this.
If Amplifier Actual Version is 00017500/xxxx or greater then it is OK to update using the update CD.
Required Updates:
1) If PCM is version 04035xxx then apply updates in this order:
Level A, Level B, Phone, and Level C.
2) If PCM is version 04202xxx then apply updates in this order:
Level B, Phone, and Level C.
3) If PCM is version 05024xxx then only apply Level C update.
4) If PCM is version 05395xxx then no updates are required, just insert the map disk.
Update Disk Part Numbers (9x7):
Level A - 000.043.205.46.004 (previously 000.043.205.46.001) – Updates Standard Production Status to Model Level A
Level B - 000.043.205.46.002 - Updates Level A to Level B
Phone - 000.043.205.46.003 - Updates Motorola phone module, if installed. Not required if phone module is not fitted.
Level C - 000.044.901.40 - Updates Navigation Module, after Level B is installed, to Level C.
Important: Levels A, B and Phone are done with a disk in the PCM CD drive. Level C is done with a CD in the Navigation drive.
Note also that different update disks are required for Cayenne models.
Edit 30th October 2012:
Just to update this a little, I have just purchased the latest map DVD for Europe, which is 08.2012. Not cheap, at just over £300 +VAT. Part number 997.044.903.50.
There are no further software updates, and it was plug & play in my sysetm. Still only partial postcode searches, and the map data files on the disk are 02.2012, so 3 and a bit years newer than the last one.
